fix up positioning of verbose cursor if it is too close to the bottom of the canvas (for MidiRegionView)
many changes to get the cairo-canvas version much, much more functional. still problems with a lot of subtle and not-so-subtle issues
add (bezier) curves to canvas, use for automation lines; fix issue with rectangles missing their upper line segment; more cairo canvas fixes
Merge branch 'cairocanvas' of git.ardour.org:ardour/ardour into cairocanvas