Forgot to initialize _selection region in canvas init method (caused crash in sequence editor).
pattern::note() converted to pattern::duration() which is in tick_t units instead of fraction of a bar.
Added grid::default_velocity() virtual method which returns the default velocity.
Implemented ::default_velocity() and velocity() methods in pattern.
SMF save/load modified to add an additional "dur=" tick_t field to the pattern proprietary chunk, keeping note= fractional bar duration for backwards compatibility.
Removed Note 1/ duration combo widget and replaced with duration slider.
Added a duration choice widget which has Snap, Beats, Bars and Ticks for different duration modes.
Moved some widgets around.
Got rid of drag_note in canvas::handle() and replaced with drag_velocity (only place it was used).
New notes now use initial velocity from new default_velocity() method of grid.
Some code reformatting.