Tidy up private message logic.
h4x: Add magic words to flag friendly users.

This is predominately used to flag myself as friendly behind the scenes
while I'm trapped behind a Windows proxy that proper IRC clients cannot
talk through. The freenode web chat client sucks, and among the things
that make it suck is maintaining a Web chat hostmask even if you
identify with NickServ. This is an ugly workaround until I can figure
out something better.
Build incremented: 0.0.53 => 0.0.54.