Replace `protected` object in active context with protected attributes on term definitions

[dlongley]

If possible, we should remove the extra protected object that is tracking whether or not certain terms are protected -- as this information is being added to the term definition in PR #312. Hopefully we can simplify.

[dlongley]

I believe this simplification has already happened (I don't see a protected object on active context but I do see protected attributes on term definitions). Closing.