Eliminate a ton of unnecessary complete redrawing in MIDI stream views:

Eliminate a ton of unnecessary complete redrawing in MIDI stream views:
Only resize vertically (don't reaload model) on range changes.
Keep track of range in model while loading (writing to model), rather than double display MIDI regions to find out.
Don't go crazy and chew CPU blinking around and doing nothing on initial show of MIDI track context menu.
Change radio 'full range' and 'contents range' menu items to non-radio actions that just set the range appropriately.
Fix crashes on some esoteric case of control data I can't figure out, but fixed anyway, so I guess it all worked out well in the end for everybody.

git-svn-id: svn://localhost/ardour2/branches/3.0@3794 d708f5d6-7413-0410-9779-e7cbd77b26cf