remove Netflix from license header (#755)

CONTRIBUTING.md

@@ -32,7 +32,7 @@ If you are adding a new file it should have a header like this:
 
 ```
 /**
- * Copyright 2013 Netflix, Inc.
+ * Copyright 2012 The Feign Authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.

HACKING.md

@@ -12,7 +12,7 @@ Code design is opinionated including below:
 
 ## How to request change
 The best way to approach something not yet supported is to ask on
-[gitter](https://gitter.im/Netflix/feign) or [raise an issue](https://github.com/Netflix/feign/issues).
+[gitter](https://gitter.im/OpenFeign/feign) or [raise an issue](https://github.com/OpenFeign/feign/issues).
 Asking for the feature you need (like how to deal with command groups)
 vs a specific implementation (like making a private type public) will
 give you more options to accomplish your goal.

LICENSE

@@ -187,7 +187,7 @@
       same "printed page" as the copyright notice for easier
       identification within third-party archives.
 
-   Copyright 2012 Netflix, Inc.
+   Copyright 2012 The Feign Authors
 
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.

NOTICE

 Feign
-Copyright 2013 Netflix, Inc.
+Copyright 2012 The Feign Authors.
 
 Portions of this software developed by Commerce Technologies, Inc.