Implemented glyph substitution table parsing and lookup tables
- ILookupSubtable.as now implements the performLookup function.
- Classes implementing ILookupSubtable.as now implement the performLookup function, at the very least by throwing a "not yet implemented" error.
- ContextualSubstitutionTableSubtableParser.as added
- ChaningContextualSubstitutionSubtableParser.as added
- HardwareCharacterInstanceListElement.as added
- ScriptFeatureLookupTable.as can now apply it's data to linked lists of hardware character instances.
- ScriptFeatureLookupTable.as can now return lookup table vectors for it's features.