Stop trying to load an awful-resource:// once we know it won't work.
Formatting.
Fix crash rendering posts when logged-in user's name is unknown.

This can happen if the user's been logged out on the server (e.g. due to a
password reset) but Awful starts restoring state before finding out that its
session was destroyed.
Fix crash loading ignored posts in a page with some hidden (i.e. previously read) posts.
Fix crash updating a thread from a managed object context that's not its own.