Optionally change the title of the profile fieldset

Having the user terms fieldset on the user's profile be labeled as "User terms" is very confusing for most users. This title should either be configurable, or set to the name of the vocabulary being used. I'd rather it have something more easily-understood, like "My tags".

I think it would make the most sense if there was a fieldset for each vocabulary (if you're using multiple vocabularies) where the title was the vocabulary, and the terms were listed below.