Remove creation of synthetic accessor method.

Updated leakcanary version.

Updated dagger2 version.

Updated rxjava version.

Updated appcompat library version.

Updated build tools version.

Updated gradle wrapper and gradle build tools.

Added checking if subscriber is still subscribed.

Added another possible way to init the SplashLibrary.

Removed redundant 'initialized' variable.

Updated RxJava.

Now using WeakReference for holding Activity.

Added more ways of emitting initialized library.

Removed unused dependencies.

Added 2 more ways for creating an Observable.