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
ZynAddSubFx: Fixed fltk not finding freetype header files.

In cases where the freetype headers are not in /usr/include, fltk wouldn't find ft2build.h.
Add FindWine module and use it in main CMakeLists.txt

Old CheckLibraryExists implementation didn't work on my system.
A find module should be better and also easier to maintain.
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.
ZynAddSubFX/FLTK: fixed detection of freetype2 include path once more

Commit 26665dde55cfa589f166998ea587db70cd516b68 was not complete as we have
to find the Freetype package and also look for freetype2 include path.
AutomatableModelView/ContextMenu: option for unlinking all controls

Integrated patch by Rodrigo Rodrigues da Silva which adds an option
to all AutomatableModelView's context menu allowing to unlink all
linked controls.