remove EditAtSelectedMarker for Mixbus, to match mb2. (also fix an existing thinko in the edit point selection actions) (oops:  also fix previous track selection fix so that it pays attention to the selection property of the group)
fix the visible_tracks_selector to show * when user tweaks a track height.  various experimental tweaks to visible_tracks_selector and a new zoom_preset_selector for Mixbus.
(Mixbus profile only)  tentatively remove the Zoom and Cut tools, to save space in the toolbar and reduce some highly redundant functions
Group the Rec and Monitor buttons together.  Group the Solo Isolate and Lock buttons together.  And add a method to show/hide each group in the Preferences
if a button has an icon, dont draw text as well