Several bug fixes, updates & modern improvements

Hey there,

I've fixed a few bugs / added a few features to the sample app:

- Added x-cancel support in latest draft spec.
- Cleaned up the nib UI
- Fixed missing root window warning.
- Updated project to ARC & removed obsolete Xcode project settings
- Fixing crashing EXEC_BAD_ACCESS error on iOS 5.1+

Hopefully these updates help.  

Thanks!