NotImplemented is, oddly, not an exception
Sometimes the redisplay doesn't fire properly after a popdown

So this is a kludge, but it vastly increases usability.
It's easier to set these to '' than check for None
utility for timing things
make this work before we're attached to a frontend
use self.show to display a thing :-)
mark the sender more obviously
calculate the "personal" flag ahead of time + add "outgoing flag"

Because there's no point in doing the comparisons every time it's
checked, it shouldn't *change*.  Also the outgoing flag is useful for
not accidently replying to yourself
use the new outgoing flag
split message windows better + filter-other-window