`[weak self]` and reference to delegate methods within `OPOperationQueue`. - Now in parity with Advanced NSOperations usage of `[weak self]` `let q = queue` (`strongSelf`) and optionals when referencing `self.delegate` (`if ([self delegate] && [self.del...`). - Resolves potential issue with a retain cycle similar to #16.
`[weak self]` and reference to delegate methods within `OPOperationQueue`.
- Now in parity with Advanced NSOperations usage of `[weak self]` `let q = queue` (`strongSelf`) and optionals when referencing `self.delegate` (`if ([self delegate] && [self.del...`).
- Resolves potential issue with a retain cycle similar to #16.

colinmcardell/Operative,Kabal/Operative,pronebird/Operative