Registrations

Needs AeroGear Android Core
Should mvn clean install.

Need to update quickstart for more demo testing.

Helloworld demo : https://github.com/secondsun/aerogear-push-helloworld/tree/registrations

It would have  a problem with the path to the things later on.  
Link to things : https://github.com/secondsun/aerogear-android-push/blob/registrations/.travis.yml#L32