Fix custom title and avatar parsing in profiles.

Had messed up: centred avatar/title combos; and gang tags.
Fix parsing avatar from posts.

Some people have non-avatar images like gang tags.
Clean up custom title HTML.

Similar to posts HTML: remove &#13; encoded carriage returns and <b/>
day-ruining would-work-if-html-was-xml tags.
Fix parsing new Forums design.

Updated the changed fixtures, then made tests pass. Main issue was not parsing
the right page number of number of pages from a page of posts. Since the new
layout is "not set in stone" according to @Choochacacko, we'll keep the old
parsing code as a fallback.
Fix crash when a thread has no tag.

Don't bother searching for updated tags if we don't have one to search for.
Implement bookmarks parsing tests.

An empty test is not very helpful. Implementing the tests uncovered a thread
tag parsing bug.
Update thread list fixture and pass tests.
Fix crash on log out.

New-style tab bar doesn't work like the old one.
Refresh forums more often.

Refreshing on appear now also happens when there are no forums, and when there
are any forums that were created as part of parsing posts.
Push built-in browser, don't show modally.

Nicer flow in my eyes.
Give built-in browser a default title.
Push user profile, instead of modal, on iPhone.

Feels nicer.
Fix saving parsed user profiles.

By not setting the user ID we were creating then updating a User instance with
a nil user ID. This appeared in the interface when viewing a profile that had
e.g. an AIM username, then viewing a profile that did not. The first user's AIM
username would erroneously appear under the second user.
Clear unset user profile entires when saving.

If someone deletes their e.g. AIM username, we should too.
Fix subforum cells' wrong color on appear.

On retheme (and therefore on appear) we were not passing in the right index
path for each visible cell. They thus inherited the background color of
(presumably) the first cell.
Default to off for highlighting mentions/quotes.

It's confusing if you're not aware of it. Whereas if you like the feature, you'll think to check Settings for it.