Fixed typo in LICENSE and renamed to md.

Author: stffabi

LICENSE LICENSE.mdLICENSE renamed to LICENSE.md

@@ -186,7 +186,7 @@
       same "printed page" as the copyright notice for easier
       identification within third-party archives.
 
-   Copyright 2015 Watchtowner contributors
+   Copyright 2015 Watchtower contributors
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.