Extended ActionFilter to also enable filtering the response side

Enables filtering the actions on both sides - request and response. Also added a base class for filter implementations (cleans up filters that only need to filter one side)
I disagree here actually... I believe that the test method describes best the scenario that you're testing, and having too long method names become unreadable. I like puting `_` in test method names cause it makes them more readable and descriptive.