Feature libs removal to support maven

The following has taken place in this branch, all is to be able to deploy to maven, without dependencies.

* Replaced volley with maven lib
* Check if Crashlytics is available as dependency
  * if true, the logger will log to crashlytics
  * no error anymore if app doesn't include crashlytics
* Moved Analytics to Jeff-for-Android (updated version, required Google play services)

@nhaarman @TheN1ckname