Android camera capture/renderer library requirements:
a- _CameraFramesCapturer_
-open/start camera capturing API
-produce YUV420 frames
-deliver frames to Callback
-close/stop camera capturing API
b-_CameraFramesViewer_:
-has open/close API
-has method to receive and draw YUV420 frames
-can display up to 4 frames at the same time (different positions)
c-_Small app to test lib_