Multi-instance support

Only works in the GUI for now, doesn't break  the command-line client but the new options are not implemented.

Related to #29 
Wait... If not not cached any, *and* not cached any... Well, not not cached is cached, and not cached is the opposite of that, and they're anded together, so...

This line really needs a comment. I can't tell what it's supposed to be doing or testing for.