Create ReadMe.md

Author: IanDarwin

GcmMockServer/ReadMe.md

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+GcmMockServer
+=============
+
+This standalone Java program works with the Google Cloud Messaging service and the simple GCM client
+defined in [../GcmClient](https://github.com/AndroidCook/Android-Cookbook-Examples/tree/master/GcmClient). 
+You really need to read the Android Cookbook recipe at
+https://androidcookbook.com/Recipe.seam?recipeId=4601 to figure out all the moving pieces!