Mapping generic classes like PINImage, PINImageView and PINButton to the equivalent UIKit or AppKit classes. Throughout the framework use these mappings instead of the concrete UIKit / AppKit names. Furthermore we provide a category on NSImage that is adding methods that are not available on NSImage but on UIImage.
Previously the resultType was being returned
PINRemoteImageResultTypeDownload even when the download failed. Now, we
check to see if the image has been set and if it not then we return
PINRemoteImageResultTypeNone.
