iOS 7 Updates

- Updated background arrow rendering and default values to more closely match iOS 7
- Changed appearance to be instant and dismissal to fade (like native iOS 7 popover)
- Fixed a bug that prevented tint from being reset when the view originally presented from is no longer in the view hierarchy
- Added an additional case to topViewControllerContentSize that references the popoverContentSize of the popover itself.
- Changed keyboard handler methods to not animate because of the way the popover is drawn it causes strange animation artifacts.