Added build flavour support to different app stores (google play, github and fdroid now supported)
Fix for #1016: Added support to rewrite the Android versionName and versionCode on the fly without touching the original AndroidManifest.xml so that we're not changing it every version bump.
Swapped out the github mozilla-services Ivy repository in preference for jcenter to satisfy f-droid requirements.
Test target wasn't using product flavor
Merge pull request #1177 from crankycoder/features/1025-fdroid

Features/1025 fdroid
added product flavor to the debug and install_debug targets