Midi: added constants for pitch bend
New header file Pitch.h for pitch-related data types and helpers
InstrumentTrack: fixed midiPitch() and added midiPitchRange()
Midi: added constants for Register Parameter Numbers (RPN) support
AutomatableModel: do not change init value when adjusting range

This causes e.g. the default value of the pitch model to be changed
when changing the pitch range.
InstrumentTrack: replaced numbers by newly introduced constants
InstrumentTrack: coding style fixes
InstrumentTrack: send RPN update in updatePitchRange()

When changing the pitch range all we can do for MIDI is to update the
MIDI pitch bend sensitivity RPN even though this is only supported by
some MIDI instruments.

Closes #129.
Sf2Player: update pitch wheel sensitivity based on pitch range

Fluidsynth supports setting the pitch wheel sensitivity, therefore make
use of it and set values from the recently introduced pitch range model.
ZynAddSubFX: default pitch wheel bend range to 100

Even though ZynAddSubFX does not support pitch wheel sensitivity RPN
events and thus we can't update the pitch range from LMMS automatically,
at least default to 100 semitones pitch wheel bend range so behaviour
is consistent with default pitch range in LMMS.
InstrumentTrack: fixed range for pitch model