Adding timelapse capture from videocamera.

Current implementation looks at the timestamps of all incoming frames in
CameraSource::dataCallbackTimestamp().
It drops all frames until enough time has elapsed to get the next time lapse frame.
When enough time has passed to capture the next time lapse frame, the frame is no longer dropped
and the timestamp of this frame is modified to be one frame time (1/framerate) ahead of the
last encoded frame's time stamp.

Change-Id: I82b9d5e96113dffa6901aac3b8a8ef999ffc1d0b