basic control structure for changing the "init MIDI" resp. "restart MIDI" button in every CVWidgetEditor resp. CVWidgetMSEditor set up in CVWidget:*prInitMidiDisplay

Signed-off-by: nuss <st9fan@gmail.com>
MIDI-sources drop-down menu added in CVWidgetEditor resp. CVWidgetMSEditor

Signed-off-by: nuss <st9fan@gmail.com>