Fleshed out PitchMaker.
Refactored NonsemanticPitchMaker around PitchMaker.
Refactored HarmonicFieldPitchMaker around PitchMaker.
Renamed NonsemanticPitchMaker to PitchMaker.
Added PitchClassPitchMaker.
Streamlined RegisterSpecifier.
Added RegisterSpecifierInventory.