Commands flagged with NoAutoSelect will not auto select, even if the user has asked for it. This is used for Cut and 3 different kinds of delete. We later might extend it to fades and repair.
Additionally, fix the UI portions of these, and fix Trim for note tracks
(the code already existed, but due to flags would not work). As PRL
requested, this is gated only behind USE_MIDI.
This commit adds note tracks into the mixerboard. It's done as a separate
slider this time instead of via subclasses (as PRL requested), so which
should be easier to use.
This also changes some of the gaurds to EXPERIMENTAL_MIDI_OUT from
USE_MIDI, as it's meaningless to have the note track code in mixerboard
when it cannot do anything (depends on methods that exist behind
EXPERIMENTAL_MIDI_OUT).