pitch automation in piano roll doesn't require first point to be 0
points are shown in the correct scale
draw discrete and linear differently
Merge pull request #41 from grejppi/stable-0.4-pitchautomation

WIP: Pitch automation improvements in Piano Roll
Prevent piano roll window from being resized to 0px height (http://sourceforge.net/p/lmms/patches/43/)
Merge pull request #45 from grejppi/stable-0.4-pianorollresize

Prevent piano roll window from being resized to 0px height