Add some iOS 7 additions and warning suppressions.

On the whole it is to make life easier.
Make the black styling appear on iOS 6.1 and below.
Suppress the deprecation warning of using segmentedControlStyle. It is wrapped in a if statement to make sure it only runs in iOS 6.1 on below.
Add a iOS 7 image to the README
Merge pull request #2 from NebulaFox/master

Merged pull request regarding iOS 7 from NebulaFox.