Added notification stretching animation
Changed UITextView to UILabel and updated stretchiness animations
Fixed stretching foreground image issue
Optimized sizing of bubbleView by caching the CGRect.  Improved UI by making animation only for when sending back to original position.
Refactored to improve UX -- before, cells were choppy for a variety of reasons like 1.) not removing NSNotifications, 2.) NSDateFormatter (thanks Nick!), 3.) too many animations at once.

The refactor -- only 1 NSNotification is added now on JSMessagesViewController rather than in each JSBubbleMessageCell.  NSDateFormatters are for the most part static (except in the MHPrettyDate lib).  And it only animates when it moves back to the original position.  It is a lot smoother now.
Reduced size of textView label by 4px
Merge remote-tracking branch 'origin/stretch_notification'

Conflicts:
	JSMessagesViewController/Classes/JSBubbleMessageCell.m