Use separate thread+socket to write video frames to server
* use QFuture to start "writePendingDatagrams()" in a separate thread
* updated RingQueue::get(ulong) to return after a given timeout
* use QWidget instead of OpenGL QGLWidget
* added parameter "validate" to "isComplete()" to do an exact evaluation of the data
Merge branch 'master' of github.com:mfreiholz/webcam-streaming-client