[PrettyTableViewCell] Correctly initialize from a storyboard.

UIStoryboard calls `initWithCoder:`.
Merge commit '734653ee4a41c7d44dd15f0401b34d598353a992'
Basic iPhone 5 adaptation
Conversion to ARC
iOS 6 compatibility
Storyboard example
Fix compatibility with iOS 4
Fix retain cycles in blocks.
Fix storyboard warning.
Merge commit 'fb2531e3f41964782e0135a6e3bef544fea0e9af'
Fix retain cycles in block after previous merging.
Merge remote-tracking branch 'kypselia/master'

Conflicts:
	PrettyKit/Cells/PrettyTableViewCell.m