Nicer two-line titles and ditch Auto Layout for Forum cells.

* Couldn't figure out the Auto Layout way to shrink the font size for two-line
  titles.
* This way also happens to be far less code, so I'm calling it success.
Move private message table view cell off Auto Layout.

Going on a purge. Also the cell separator is now set appropriately regardless
of the thread tag's appearance.
Lay out main view after switching from basement.

Animating e.g. a table view into position looks stupid.
Exorcise Auto Layout from thread cell.

Bonus: fix that bug where the wrong ratings would appear for a thread. The bug
occurred when a cell, previously used by a thread with a rating, was reused by
a thread with a rating. The updated rating image was never used.
One long press recognizer per thread cell is plenty.

Just realized we were inadvertently adding a new recognizer every time a cell
got reused.