Added support for multiple users as arguments for owner, op, halfop, voi...

...ce, and quiet.

One can also prefix nicks with - for negative, or + for positive.
op #Test Foo -Bar
will op Foo, and deop Bar
deop #Test Foo +Bar
will deop Foo and op Bar

closes #105

I put this in again rather than rebase, as I wasn't able to get everything as needed with rebasing.