Improves sound device selection: automatically switches to new plugged device, remember user preferences in a list.

- Works on removing the video of a video conference participant from display on the remaining non-focus participants. - Tries to fix a crash in PortAudio (often seen at the end of video conference calls).

Fixes an issue which would leak at least one Thread per call which would endlessly send out RTCP packets.

Fixes a failure to keep the aspect ratio of the video when switching to full screen. Attempts to remedy a multi-video display when switching between camera and desktop streaming. Tries to fix a crash in the QTKit video capture on Mac OS X. Works on addressing a unnecessary remaining of the camera on Mac OS X open.

Re-applies the ideas of r9718 with a refined implementation on the PulseAudio Renderer in order to reflect changes to the user's choice with respect to the default playback device while in a call.

Temporarily reverts to the PulseAudio Renderer implementation to a pre-r9718 state to fix freezes reported by Vincent Lucas and Kertesz Laszlo on the dev mailing list while further looking into the cause of the problem.

Commits an initial version of the libjitsi library which should be fully functional with respect to neomedia/MediaService and should be usable with and without OSGi.