[FEAT] Doxygen comments for code

[aburrell]

Is your feature request related to a problem? Please describe. Some of the code features and attributes could use more explanation

Describe the solution you'd like Although this is general and ongoing, I would specifically (for this issue) like to see:

• [ ] descriptions of the existing classes
• [ ] reasons behind different dimensions (nGeoAlts)
• [ ] makefile flags

Describe alternatives you've considered Not making a note of specific areas that I think need comments and leaving it to chance.

Additional context Items noted for future improvement in PR #31