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)
the recursive nature of the filters is actually not related to this specific issue here... but while on the subject, the goal here was to create a async filtering pipeline... if I understand you correctly (might be that I'm not), a loop will block.

As for this specific issue, the question was whether to use the same chain for both sides (request & response)... and we could... but that means we'll loose the handling of the "too many calls for continueProcessing" errors.