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
Trackoperations widgets, stylesheet changes, fix of the bug where palette goes all white if stylesheet has no palette
New graphics for FX faders, some stylesheet changes. The changes in fader.cpp are just colour changes
Update to fx fader knob, changed fade_button (the blinky thing in instrument tracks)  to comply with palette