I couldn't easily find any documentation.  I didn't add these classes, can we not block the PR on me adding documentation about the purpose of classes that I didn't add?

I felt that  "A wrapper around CommCareCases to get more built in functionality specific to supply point products." provides no information not available in `class SupplyPointProductCase(CommCareCase)` so I removed it when I originally made a CommTrackCase base class and felt stupid renaming CommCareCase in the docstring to CommTrackCase.