GNU General Public License
==========================

_Version 3, 29 June 2007_  
_Copyright © 2007 Free Software Foundation, Inc. &lt;<http://fsf.org/>&gt;_

Everyone is permitted to copy and distribute verbatim copies of this license
document, but changing it is not allowed.

## Preamble

The GNU General Public License is a free, copyleft license for software and other
kinds of works.

The licenses for most software and other practical works are designed to take away
your freedom to share and change the works. By contrast, the GNU General Public
License is intended to guarantee your freedom to share and change all versions of a
program--to make sure it remains free software for all its users. We, the Free
Software Foundation, use the GNU General Public License for most of our software; it
applies also to any other work released this way by its authors. You can apply it to
your programs, too.

When we speak of free software, we are referring to freedom, not price. Our General
Public Licenses are designed to make sure that you have the freedom to distribute
copies of free software (and charge for them if you wish), that you receive source
code or can get it if you want it, that you can change the software or use pieces of
it in new free programs, and that you know you can do these things.

To protect your rights, we need to prevent others from denying you these rights or
asking you to surrender the rights. Therefore, you have certain responsibilities if
you distribute copies of the software, or if you modify it: responsibilities to
respect the freedom of others.

For example, if you distribute copies of such a program, whether gratis or for a fee,
you must pass on to the recipients the same freedoms that you received. You must make
sure that they, too, receive or can get the source code. And you must show them these
terms so they know their rights.

Developers that use the GNU GPL protect your rights with two steps: **(1)** assert
copyright on the software, and **(2)** offer you this License giving you legal permission
to copy, distribute and/or modify it.

For the developers' and authors' protection, the GPL clearly explains that there is
no warranty for this free software. For both users' and authors' sake, the GPL
requires that modified versions be marked as changed, so that their problems will not
be attributed erroneously to authors of previous versions.

Some devices are designed to deny users access to install or run modified versions of
the software inside them, although the manufacturer can do so. This is fundamentally
incompatible with the aim of protecting users' freedom to change the software. The
systematic pattern of such abuse occurs in the area of products for individuals to
use, which is precisely where it is most unacceptable. Therefore, we have designed
this version of the GPL to prohibit the practice for those products. If such problems
arise substantially in other domains, we stand ready to extend this provision to
those domains in future versions of the GPL, as needed to protect the freedom of
users.

Finally, every program is threatened constantly by software patents. States should
not allow patents to restrict development and use of software on general-purpose
computers, but in those that do, we wish to avoid the special danger that patents
applied to a free program could make it effectively proprietary. To prevent this, the
GPL assures that patents cannot be used to render the program non-free.

The precise terms and conditions for copying, distribution and modification follow.

## TERMS AND CONDITIONS

### 0. Definitions

“This License” refers to version 3 of the GNU General Public License.

“Copyright” also means copyright-like laws that apply to other kinds of
works, such as semiconductor masks.

“The Program” refers to any copyrightable work licensed under this
License. Each licensee is addressed as “you”. “Licensees” and
“recipients” may be individuals or organizations.

To “modify” a work means to copy from or adapt all or part of the work in
a fashion requiring copyright permission, other than the making of an exact copy. The
resulting work is called a “modified version” of the earlier work or a
work “based on” the earlier work.

A “covered work” means either the unmodified Program or a work based on
the Program.

To “propagate” a work means to do anything with it that, without
permission, would make you directly or secondarily liable for infringement under
applicable copyright law, except executing it on a computer or modifying a private
copy. Propagation includes copying, distribution (with or without modification),
making available to the public, and in some countries other activities as well.

To “convey” a work means any kind of propagation that enables other
parties to make or receive copies. Mere interaction with a user through a computer
network, with no transfer of a copy, is not conveying.

An interactive user interface displays “Appropriate Legal Notices” to the
extent that it includes a convenient and prominently visible feature that **(1)**
displays an appropriate copyright notice, and **(2)** tells the user that there is no
warranty for the work (except to the extent that warranties are provided), that
licensees may convey the work under this License, and how to view a copy of this
License. If the interface presents a list of user commands or options, such as a
menu, a prominent item in the list meets this criterion.

### 1. Source Code

The “source code” for a work means the preferred form of the work for
making modifications to it. “Object code” means any non-source form of a
work.

A “Standard Interface” means an interface that either is an official
standard defined by a recognized standards body, or, in the case of interfaces
specified for a particular programming language, one that is widely used among
developers working in that language.

The “System Libraries” of an executable work include anything, other than
the work as a whole, that **(a)** is included in the normal form of packaging a Major
Component, but which is not part of that Major Component, and **(b)** serves only to
enable use of the work with that Major Component, or to implement a Standard
Interface for which an implementation is available to the public in source code form.
A “Major Component”, in this context, means a major essential component
(kernel, window system, and so on) of the specific operating system (if any) on which
the executable work runs, or a compiler used to produce the work, or an object code
interpreter used to run it.

The “Corresponding Source” for a work in object code form means all the
source code needed to generate, install, and (for an executable work) run the object
code and to modify the work, including scripts to control those activities. However,
it does not include the work's System Libraries, or general-purpose tools or
generally available free programs which are used unmodified in performing those
activities but which are not part of the work. For example, Corresponding Source
includes interface definition files associated with source files for the work, and
the source code for shared libraries and dynamically linked subprograms that the work
is specifically designed to require, such as by intimate data communication or
control flow between those subprograms and other parts of the work.

The Corresponding Source need not include anything that users can regenerate
automatically from other parts of the Corresponding Source.

The Corresponding Source for a work in source code form is that same work.

### 2. Basic Permissions

All rights granted under this License are granted for the term of copyright on the
Program, and are irrevocable provided the stated conditions are met. This License
explicitly affirms your unlimited permission to run the unmodified Program. The
output from running a covered work is covered by this License only if the output,
given its content, constitutes a covered work. This License acknowledges your rights
of fair use or other equivalent, as provided by copyright law.

You may make, run and propagate covered works that you do not convey, without
conditions so long as your license otherwise remains in force. You may convey covered
works to others for the sole purpose of having them make modifications exclusively
for you, or provide you with facilities for running those works, provided that you
comply with the terms of this License in conveying all material for which you do not
control copyright. Those thus making or running the covered works for you must do so
exclusively on your behalf, under your direction and control, on terms that prohibit
them from making any copies of your copyrighted material outside their relationship
with you.

Conveying under any other circumstances is permitted solely under the conditions
stated below. Sublicensing is not allowed; section 10 makes it unnecessary.

### 3. Protecting Users' Legal Rights From Anti-Circumvention Law

No covered work shall be deemed part of an effective technological measure under any
applicable law fulfilling obligations under article 11 of the WIPO copyright treaty
adopted on 20 December 1996, or similar laws prohibiting or restricting circumvention
of such measures.

When you convey a covered work, you waive any legal power to forbid circumvention of
technological measures to the extent such circumvention is effected by exercising
rights under this License with respect to the covered work, and you disclaim any
intention to limit operation or modification of the work as a means of enforcing,
against the work's users, your or third parties' legal rights to forbid circumvention
of technological measures.

### 4. Conveying Verbatim Copies

You may convey verbatim copies of the Program's source code as you receive it, in any
medium, provided that you conspicuously and appropriately publish on each copy an
appropriate copyright notice; keep intact all notices stating that this License and
any non-permissive terms added in accord with section 7 apply to the code; keep
intact all notices of the absence of any warranty; and give all recipients a copy of
this License along with the Program.

You may charge any price or no price for each copy that you convey, and you may offer
support or warranty protection for a fee.

### 5. Conveying Modified Source Versions

You may convey a work based on the Program, or the modifications to produce it from
the Program, in the form of source code under the terms of section 4, provided that
you also meet all of these conditions:

* **a)** The work must carry prominent notices stating that you modified it, and giving a
relevant date.
* **b)** The work must carry prominent notices stating that it is released under this
License and any conditions added under section 7. This requirement modifies the
requirement in section 4 to “keep intact all notices”.