Use new enum declaration.

The new(er) NS_ENUM declaration makes dealing with enumerated values in Swift really nice.
Fix for deprecated sizeWithFont: method in iOS 8 SDK
Properly handle orientation changes across iOS 7 and 8.
Merge pull request #336 from krzysztofzablocki/master

Properly handle orientation changes across iOS 7 and 8.
Merge pull request #335 from edwardmp/master

Fix for deprecated sizeWithFont: method in iOS 8 SDK
Merge pull request #332 from calebd/master

Use new enum declaration.
Multiple UIWindow support
Use isHidden instead of isKeyWindow because isKeyWindow is somehow not correctly updated