Automatic class id generation

[jumpinjackie]

• Update preparation tools to properly rewrite class id include paths in SWIG parameter file (instead of commenting them out)
• Run SWIG in XML mode to generate the XML dump of the MapGuide API surface
• Update the ClassMapGen tool to take the SWIG XML dump file and scan all the m_cls_id members for their values. These values will most likely be arithmetic expressions, so the actual id will need to be evaluated (maybe use exprtk to do this)Auto-generate the class map templates from this collected data.