Probably all of the useful devices are now reported by capabilities, so
it's likely to be not even needed, so to avoid confusion it's moved into
the settings window and given a more descriptive name
Since QTextEdit::setTabStopDistance() is available starting 5.10 and we
still support Qt 5.5 (Ubuntu 16), it's moved to log_window.cpp and
ifdefed according to version
* 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
