Migrate to MIT license

Adapted to the MIT license migration of the main "Nord" (1) project.
Detailed information can be found in the main task ticket.

All license SVG badges and the "LICENSE.md" content have been updated.
In addition all source code comment header have also been simplified.

References:

* (1) https://github.com/arcticicestudio/nord

Subtask of nordtheme/nord#55
GH-4

LICENSE.md

@@ -0,0 +1,22 @@
+MIT License (MIT)
+
+Copyright (c) 2017-present Arctic Ice Studio <development@arcticicestudio.com> (http://arcticicestudio.com)  
+Copyright (c) 2017-present Sven Greb <code@svengreb.de> (http://svengreb.de)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

Nord.tmTheme

@@ -1,20 +1,17 @@
-<?xml version="1.0" encoding="UTF-8"?>
 <!--
-+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-title      Nord Sublime Text                                    +
-project    nord-sublime-text                                    +
-repository https://github.com/arcticicestudio/nord-sublime-text +
-version                                                         +
-author     Arctic Ice Studio                                    +
-email      development@arcticicestudio.com                      +
-copyright  Copyright (C) 2017                                   +
-+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
-[References]
-Sublime Text
+Copyright (c) 2017-present Arctic Ice Studio <development@arcticicestudio.com>
+Copyright (c) 2017-present Sven Greb <code@svengreb.de>
+
+Project:    Nord Sublime Text
+Repository: https://github.com/arcticicestudio/nord-sublime-text
+License:    MIT
+References
   https://www.sublimetext.com/docs/3/color_schemes.html
   https://www.sublimetext.com/docs/3/themes.html
   https://www.sublimetext.com/docs/3/scope_naming.html
 -->
+
+<?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
 <plist version="1.0">
   <dict>

README.md

@@ -110,9 +110,9 @@ Please report issues/bugs, feature requests and suggestions for improvements to
 
 <p align="center"><img src="https://cdn.rawgit.com/arcticicestudio/nord/develop/src/assets/banner-footer-mountains.svg" /></p>
 
-<p align="center">Copyright &copy; 2017 Arctic Ice Studio</p>
+<p align="center">Copyright &copy; 2017-present Arctic Ice Studio</p>
 
-<p align="center"><a href="http://www.apache.org/licenses/LICENSE-2.0"><img src="https://img.shields.io/badge/License-Apache_2.0-5E81AC.svg?style=flat-square"/></a> <a href="https://creativecommons.org/licenses/by-sa/4.0"><img src="https://img.shields.io/badge/License-CC_BY--SA_4.0-5E81AC.svg?style=flat-square"/></a></p>
+<p align="center"><a href="https://github.com/arcticicestudio/nord-sublime-text/blob/develop/LICENSE.md"><img src="https://img.shields.io/badge/License-MIT-5E81AC.svg?style=flat-square"/></a> <a href="https://creativecommons.org/licenses/by-sa/4.0"><img src="https://img.shields.io/badge/License-CC_BY--SA_4.0-5E81AC.svg?style=flat-square"/></a></p>
 
 [doc-ui-theme]: https://www.sublimetext.com/docs/3/themes.html
 [nord-pc]: https://packagecontrol.io/packages/Nord