Extract menus etc. to UITextView subclass.

UITextView handles a menu for cut/copy/paste, define, and suggest. It seems
reasonable for Awful to have a subclass adding its own baseline menu items.
Create superclass compose view controller.
Start of private message compose view.
More extraction into AwfulComposeViewController.

Then the private message compose controller can share!
Documentation.
To and subject fields for private message compose view.
Show compose views modally as page sheet.
Parse private message compose screen for post icons.
Remove unused fixture.
Hello PSTCollectionView!
Post icon picker.
Fix rudely-dismissed PM compose view.

Comment explains what was going on.
Handle rotation with visible post icon picker.
Send private messages, including replies and forwards.
PM composer updates ivars from text fields.

Notably, sending now works.