Add a border to the Preferences scrollview
Add a label to Preferences view
Removing some extraneous comments

Hopefully this is all pretty straightforward
WIP: show channels for selected server in preferences
Make subviews for servers & channels in app prefs
Make delete server button in preferences work again
Factor more stuff out of AppDelegate
Fix an edge case in applicationShouldTerminate

It was previously possible for the app to get in an infinite loop
where it was not possible to quit because saving models would fail
over and over again.