Rename LICENSE to LICENSE.md, convert its content to Markdown format

LICENSE.md

@@ -7,7 +7,8 @@ Copyright © 2012      Philipp Balzarek
 
 Licensed under the Apache License, Version 2.0 (the "License"); you may not use
 this file except in compliance with the License. You may obtain a copy of the
-License at <http://www.apache.org/licenses/LICENSE-2.0>.
+License at
+[http://www.apache.org/licenses/LICENSE-2.0](http://www.apache.org/licenses/LICENSE-2.0).
 
 Unless required by applicable law or agreed to in writing, software distributed
 under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR