Add getters+setters for enabling map gestures on Android

[matteblair]

This creates a simple way to enable or disable some or all of the gestures that can be used to change the map view.

On iOS this can be achieved by accessing the gesture recognizers directly like:

mapView.rotationGestureRecognizer.enabled = NO;

On Android this now leaves us with some potentially redundant interfaces. The gesture responder interfaces can be used to pre-empt map view changes cause by gestures, but this is no longer necessary. We can now potentially simplify these interfaces by removing return values from the methods, or even remove these gesture responders from the public interface.

[hjanetzek]

LGTM

[tallytalwar]

In reference to the PR description:

even remove these gesture responders from the public interface.

I think it probably make sense to still have public different gesture responder interfaces and give the client developer opportunity to customize these responder behaviors. But yes we can remove the boolean return values from these interface methods in favor of set*GestureEnabled methods.

[tallytalwar]

Rebasing and merging.