Remove SCORM dependancies

Relates to https://github.com/adlnet/xAPI-Spec/issues/501

This PR is **not ready to be merged** and is a work in progress. That said, I am trying to keep this in a state where it could be merged as an improvement after each commit by commenting out unfinished bit. I also appreciate comments on the general direction and specific changes so far.  

It may be that I get to a certain point with this and then put it on the back burner to focus on other, more quick-win, issues. In that event, it'd be worth merging to avoid conflicts. 
I think we should still mention which section various parts refer to in the SCORM specs, and just be very clear that such references are for descriptive and comparative purposes, and that the only conformation requirements are in this doc.