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 have to agree with luca I think this entire recursive `continueProcessing` is very confusing. I wonder if we can solve this simply interatively by returning a boolean from `process` that way we can implement this as a simple loop? Maybe I am missing the big picture?