Remove pre-10.7 code.
Many changes:
Getting rid of unneeded parentheses.
Remove more pre-10.7-only code.
Add comments.
More property declarations.
Make SUUpdatePermissionPromptDelegateInformalProtocol a protocol with the name SUUpdatePermissionPromptDelegateProtocol.
We don’t need to declare ivars in the interface block if they are only accessed via accessors.
This is only true because we’re targeting x86_64 on OS X. The same is true for all iOS architectures, but not i386 on OS X.
Use CFBridgingRelease in a few places: it acts just like [(id)CFMakeCollectable(obj) autorelease] on non-ARC code, but is a bit cleaner.