[IM] Updated MIDI actions to new architecture, way more flexible now. The Action class handles all the mapping (to collisions, proximity changes, vocal commands, whatever...).
[IM] A lot of file renaming and refactoring to reflect the fact that Actions and Mappings are separated from collision considerations, for flexibility.
[IM] [OSX] More refactoring, CollisionAction to Action, CollisionEventChain to EventChain, separated ActionType enum and Action factory methods into core.