Send -copy:(id)sender to app delegate

Unsure why you can't copy after you copy once. It seems like the
first responder is changing, but I can't be sure.
Validate hostname before connecting

If you enter something that isn't an IRC server, we shouldn't let you
connect to that at all.
chatView is a property on AppDelegate

For now, we'll only have one ChatView so this is fine.
New Server window respects AppDelegate's chatview