CRBubble can now have no title
Corner Button Support : Bubble stay on the screen + Arrow point to the attachedView
fixing width by using iOS7 methods boundingRectWithSize
use last commit only for iOS 7.0 and above
Merge pull request #6 from hefgi/bubble-width

Bubble width improvement, support of corner button (for the arrow position), CRBubble can now have no title. Thank's Hefgi.