Fix typos in AFImageRequest header file
Add initial tests for AFImageRequestOperation
Test responseImage on success and failure
Test image processing block
Renaming AFTestURLProtocol -> AFMockURLProtocol

Refactoring AFMockURLProtocol to use mocks more directly
Merge branch 'feature-ImageRequestOperationTests' of https://github.com/codepost/AFNetworking into codepost-feature-ImageRequestOperationTests

Conflicts:
	Tests/AFNetworking Tests.xcodeproj/project.pbxproj
Refactoring image request tests