Split GTWAOFRawDictionary implementation into a new GTWMutableAOFRawDictionary class.
Split GTWAOFRawQuads implementation into a new GTWMutableAOFRawQuads class.
Split GTWAOFRawValue implementation into a new GTWMutableAOFRawValue class.
Updated mutable Quads, Dictionary, and Value methods to take a GTWAOFUpdateContext instead of an id<GTWAOF> object.