Fix non-retina pages icon.
Get state restoration working on iPad for thread view, posts view.
No accessors in -init!
Preserve and restore forum list state.

Namely, which forums are expanded to reveal their subforums.
Preserve and restore state of thread lists.
Preserve and restore private message view state.
Preserve and restore PM compose view state.

Fetching the post tags in -viewDidLoad caused a crash somewhere in
NSURLConnection code, so I moved it to -viewWillAppear:.
Remove unused properties.
Commentary.
Remove AwfulPrivateMessageComposeViewController delegate.

It was only trivially implemented.

The impetus for this change was to deal with state preservation and restoration
for view controllers with delegates. The easiest way to deal with the PM
compose view's delegate was to simply remove the concept.
Update send button and title on restored PM compose view.
Save and restore thread compose view state.
Preserve and restore reply compose view state.