GCM-Server

The use of GCM-Serveris governed by the following license :

Copyright 2015 Google, Inc.
Licensed to the Apache Software Foundation (ASF) under one or more 
contributor license agreements. See the NOTICE file distributed with this work for additional information regarding 
copyright ownership. The ASF licenses this file to you 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
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 CONDITIONS OF ANY KIND, either express or implied. See the License for the specific 
language governing permissions and limitations under the License