SMF compilation rework

[marengohue]

THIS PR IS STILL IN PROGRESS

• All parts of the SMF file are now packaged up through a use of a typed SMFWriter
• SMFWriter is responsible for setting all of the data chunk offsets and for maintaining coherency between headers
• Every part of the SMF file now has a class representing it, each responsible for own data validation
• Unit test coverage on the compilation process
• Additional documentation about the Spring Map Format and the way it is structured (with BAR-specific details)
• Overall improvements to code, documentation and modularity