Default string source value is empty string
First draft of trying to make the audio work in VideoSource (not yet working)
- Cleanup and refactoring to make the video source process more tight
- Proper handling of sleeping of plugs when wrong file in input
Clear buffer adapter when changing from pause to ready and when eos reached (as recommended in GStreamer doc)
Adjustments in the handling of _terminate and reset/seeks
Better audio format (including param depth and some reordering)