React over completed state
Check for response url to avoid crash when not present

Creating a dictionary with a response that has a nil URL will crash the
app
Fixing documentation copy-paste error (AFNetworkingOperationFailingURLResponseErrorKey -> AFNetworkingOperationFailingURLRequestErrorKey)
Merge pull request #2433 from NSElvis/fix/crash-with-nil-url-in-response

Check for response url to avoid crash when not present
Refactor state of refresh control using task
Merge pull request #2432 from NSElvis/improve/UIRefreshControl

UIRefreshControl should react over task with completed state
[Issue #2381] Using static char declaration pointers for associated object keys in UIButton category
Merge branch 'master' of github.com:AFNetworking/AFNetworking
Bumping version to 2.5.0