Rearrange code for popping to root when tapping selected tab bar item.

We don't want to do it when selecting the view controller, we want to do it
when tapping the tab bar item.
Fix lame names in basement.

I was trying to make them better for VoiceOver. Oops.
Revert "Switched URL action button to UIActivityController" et al.

Not convinced it's the right way to go, and it really does look awful. Worth
revisiting, not ready now.

This reverts commit db5acb9daa8f6858dac5429821f4909fb9df9cdd.
This reverts commit cb9063806a8860988aac00de96a73832bfb3147d.
This reverts commit faabeaa5f4393abc032c78eb78b98d88b6ce2b7a.
This reverts commit 1f0ef3e27b0e211c76f2977391c6fb97bad55624.
Don't set cache name for forum tree data source.

We were seeing a crash in 2.0.3. An example crash is
http://crashes.to/s/b201e295bac. The crashing method is
-[NSFetchedResultsController(PrivateMethods) _preprocessUpdatedObjects:insertsInfo:deletesInfo:updatesInfo:sectionsWithDeletes:newSectionNames:treatAsRefreshes:].

Some searching turned up http://stackoverflow.com/a/14843264, which mentions a
crash in that method, and finds that an undetected invalid cache is the
culprit. Since we only started setting the cache name in 2.0.3, and turning off
the cache is no big loss, it seems worth trying.
Add some Crashlytics logging to figure out crash scraping messages inbox.

Crash is "This NSPersistentStoreCoordinator has no persistent stores. It cannot
perform a save operation."
Fix split view sidebar staying hidden after rotating device.

When rotating the device while some other view controller takes up the screen
(e.g. watching a video), we weren't updating the split view state to consider
the new interface orientation.
Fix dark theme setting in profile view.

Deleted the JavaScript Awful.dark function ages ago, forgetting that the
profile view still used it. Reinstated.

Bonus: rework the profile view controller a bit to make it less confusing.