event_list::select methods now select notes which have note-offs within the region and also those for which the select region lies within the note duration.
event_list::select() lo note parameter is now non-inclusive to be consistent with time end parameter.
Replaced color average for selected notes to velocity_select_colors[] array containing velocity colors.
Note drag velocity now more sensitive (don't divide by 3.0).
Fixed note drag velocity to be a minimum of 1.
[non-sequencer] Selection system overhaul:
Renamed _selection_rect to _selection.
Cursor area defined by p1, p2, p3 and p4 now replaced by _selection.
Grid selection now snapped to grid units rather than pixel.
_lr renamed to fix_selection.
Removed start_cursor and end_cursor methods.
Moved range cursor drawing to overlay and disabled (will be removed), since cursors aren't necessary now.
Changed selection box color to blue.
Added set_selection() method for conveniently assigning selection region.
Selection region now remains drawn (with alpha) after button release.
Region and Rectangle select can be cleared by not dragging after click/release.
Holding CTRL when region or range selecting adds to selection.
delete_note in Canvas::handle cleanup.
Misc. code cleanup.
Fixed CTRL left click note selection toggle.
Merge branch 'master' of https://github.com/Element-Green/non