Added proper testing of the end of quicktime video files.
Added proper testing of the end of quicktime video files.

CvCaptureFile::grabFrame() always returns 1 regardless, which causes
dead loop when relying on the return value of VideoCapture::read().

apavlenko/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,apavlenko/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,opencv/opencv,apavlenko/opencv,apavlenko/opencv,opencv/opencv,apavlenko/opencv