This patches adds preliminary Doxygen documentation to the src/core/track.cpp file.
The documentation is based on my incomplete understanding of what the various components do. In several places I have left specific /todo notes where I know that I just haven't understood something, but the whole documentation needs review by the developers to make sure that it is accurate, relevant and not misleading. Ideally this patch would be added to the source and then additional documentation added in separate commits.
I'm working on the principle that partial documentation is better than no documentation, but inaccurate documentation is worse than none.