Android: Removing unused fragments and widgets.

Removed:
* Radio Calibration
* Tuning fragment
* RC Mode setup
* OnScreen Joysticks and preferences
* SeekbarWithText widget
* NumberEditField widget
* FillBar widget
* RC override preferences
Merge pull request #1172 from DroidPlanner/cleanup_of_fragments_and_widgets

Android: Removing unused fragments and widgets.