adds piano_roll key presses
Merge branch 'stable-0.4' of https://github.com/bhattigurjot/lmms into stable-0.4
TrackContainer, TrackContainerView: adopted coding style

Renamed file and class names.
SampleBuffer, SamplePlayHandle, SampleRecordHandle, SampleTrack: new coding style

Renamed file and class names.
Merge pull request #17 from bhattigurjot/stable-0.4

PianoRoll: added support for pressed keys
Piano: refactored class to be usable without friend classes
PianoRoll: coding style improvements
Added volumeToMidi() helper function
Piano: added optional velocity argument to handleKeyPress()
PianoRoll: always use the PianoModel for note on/off + other improvements
PianoRoll: fixed typo leading to big white key at wrong position when pressed
New SF2 plugin artwork
Final tweaks to SF2 artwork (based on feedback), moved chorus & reverb buttons a bit to fit them better with new artwork
New led graphics, initial style sheet changes (work still in progress), other theme changes
Merge pull request #22 from Lukas-W/stable-0.4

Fix build problems: Find wine and freetype headers
Stylesheet changes, added palette customizability, fx mixer obeys palette, etc...
Fixed typo :P
Merge pull request #24 from diizy/stable-0.4

Merge for now and let's fix things later.