Fix trying to get key config for None window

Occasionally an event like a resize will occur while the interface is
still taking and processing keys, so screen.focused can be None. Don't
return that None in the focus list.
Add a couple more config hooks

Now that we're tracking defaults / feed configuration, this can be
propagated.
Force a tag reset / update on defaults.global_transform change
Be even lazier on NEWTAG notification

We already didn't propagate new tag calls, but now don't refresh the
config without real newtags either.