-Added a user info dictionary to the task did finish notification.
-Added some DRY methods to reduce duplicate logic.
Renaming setResponseSerializers: to setImageResponseSerializer:
Merge pull request #1272 from marcelofabri/2.0

[2.0] Fixing imageResponseSerializer setter on UIImageView+AFNetworking
Refactoring AFURLSessionManager additions
Fixing Clang warning about task being unassigned before being captured in block
Adding completionQueue and completionGroup properties to AFURLSessionManager
Merge branch '2.0' of github.com:AFNetworking/AFNetworking into 2.0
Adding removed nil checks for notification userInfo
Use notifications instead of KVO in UIActivityIndicatorView+AFNetworking
Use UIActivityIndicatorView+AFNetworking in example project
Modernize code
Using __block to fix nil task in completion handlers