This was a dirty fix for #106. Video display devices were reported with
the module name and device option (e.g. "decklink:device=0"). The
display devices are now reported as separate module name and device
option strings, which means that we can test for exact match.
This reverts commit dc9ede91f1.
* use ug --capabilities for querying
* support for webcams on Windows and MacOS
* support for decklink capturers and modes
* query v4l2 through UltraGrid
* don't store state in ui widgets (preparation for saving/loading settings)
* automatic FEC
