onCameraFrame callback signature changed. CvCameraFame interface added.

New interface allows to get one RGBA or Gray frame from camera or both in the same time;
New interface fixes data rase in samples also.
Android samples updated according onCameraFrame callback signature change.
FpsMeter class removed from Image Manipulations and Face Detection examples as unused code.
Code review issues fixed. Compatibility issues fixed.
15-puzzle app reverted to usage of old CvCameraViewListener implementation;
super.onPause() call moved to begining of onPause method according Google recomandations.
Merge pull request #402 from asmorkalov:samples_data_rase_fix