Revert "Replace long-pressing thread cells with "More" swipe accessory button."

Doesn't work all that well, certainly not well enough to risk a private API
rejection.

This reverts commit 0bdafc445d3012d277a36fae138dcda1f87218ff.
Darken dark mode secondary list color.
Formatting.
Resume downloading updated thread tags.

I guess I ripped this out at some point, presumably intending to reimplement
it, but never got around to it until now?
Tidy up AwfulThreadCell long-press action handling.

Gesture recognizer is an implementation detail.
Formatting.
Move view controller getter out to category on UIView.
Tidy up AwfulFrameworkCategories.h.

* Forgot UIColor category.
* Alphabetize.
Rewrite thread tag picker.

The new picker is simpler as it just takes an array of image names (plus an
optional array of secondary image names). The delegate no longer needs to
supply images.

In addition, the secondary tags are more nicely drawn in the picker. The
checkmark seemed superfluous with the filled-in background (plus it obscured
the title text). And the title text has more room to breathe.
New empty icons
New PostTopBar Colors
Dark(er) Mode
Better handle "database unavailable" error.

Life, lemons, etc.
Update thread tag picker with newly-downloaded thread tags.
Don't show empty thread tag picker.

Wait until we get the thread tags, and keep trying until we have them.
Remove pointless parameter from method for posting threads.

The AwfulForm knows what the key is for the secondary thread tag, no need to
pass it in (and indeed the passed-in key is not used).
Fix crash updating downloaded thread tags in picker.

Not sure why I keep thinking this is valid on NSMutableDictionary.
Wow that looked bad.
Include error in exception when moving data store.
Set Crashlytics username nice and early.