Need to allow the instructor to set enablements that will apply to anyone who
enrolls in the class thereafter.
this is a bit of a bear but i think it's the most urgent.
this will also enable the instructor to set default weights for anyone joining
the class -- when that ability is available for anyone. i need to remember this
because it's extra justification for doing this as a bit of a hack.
This beast is live. Things are a tad slow but hopefully this is working.