save solo states for tracks
Merge pull request #58 from bhattigurjot/stable-0.4

[Patch] Save solo states for tracks
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
LB302 artwork, OPL2 logo
refactor...
Fader changes
New simple transport button icons + some slight UI code tweaks
Added new artwork