Support "profiles" of active mod selections

[mxjessie]

Related to #36, it would be really nice to be able to save/clone/load/unload sets of mods and quickly toggle between them.

I like to keep as few mods loaded as necessary, and there are a handful of mods I only use while doing avatar work, or while doing lots of ProtoFlux. Toggling stuff that fiddles with the default UIs would be nice for grabbing screenshots for the wiki/mentoring purposes, etc. It'd be nice to be able to pare things down to a necessary minimum with a click or two.

This would be a very low-priority nice-to-have thing.