Missed some change update calls in recent optimization efforts, which resulted in lack of redraw when moving notes vertically at least.
Added panzoomer update to Canvas::pan which fixes redraw issues with pan related key events, introduced by recent optimization efforts.
Fixed memory leak with Grid::put when note rejected due to overlap.
Modified Grid::put so notes can now be inserted immediately before another.
Fixed crash bug when multiple notes dragged vertically up out of range.
Notes now remain selected after moving and some code reformatting.
Removed unused ruler_drawn, mapping_drawn and grid_drawn from Canvas.