Updated compatibility notes for Xcode 5.1
Fix warnings caused by -Wsign-conversion and -Wshadow-ivar.
Don't show activity indicator when imageURL is nil
When nil is set as imageURL the activity indicator is shown and never hidden. This pull request just doesn't show it in the first place.
…d above anyway
Activity indicator is not vertically centered
…unctionality. Switched to NSCache for internal caching - this means that the project now requires iOS 4 features.