Create a new chatlog if one doesn't exist

This is useful eg: when someone private messages you.
Chatlogs should not be editable by default

Only need to set the editable flag when we are inserting into them.
Set hostname when connecting to a server

Considered that maybe the best place to do this would be in the
didConnect handler when we find out the *real* hostname of the
server that we should expect to get messages from.

eg: for chat.freenode.net, you can expect to get messages back from
any number of smaller servers that provide functionality for
freenode.net
Comment this CoreData exception better

Hoping this never happens when I release, but it would be nice to
be able to know if this was happening.
Handle window resize

I really wanted to just use autolayout, but my autolayout-fu is not
strong enough to handle this simple layout. I just wanted to have
all of the three views (tabs, chat log, and text input be stacked
one of top of the other vertically and fill the entire view, but
that seemed to be difficult to implement, for some unknown reason.