Delete unused "start view controller".
Rearrange Data group in xcodeproj.
Forums list controller no longer is its own restoration class.

We want the app delegate to handle things, which only happens if there's no
restoration class set.
Reload the forums list after restoring state.

The table view's row data is invalid once the tree controller is restored.
Bookmarks controller doesn't need a restoration class.

App delegate can handle it.
Redo posts view controller API to take actual objects.
Bookmarks controller no longer inherits from thread list controller.

Never really made sense. They do share lots of code though, should factor that
out.