Api versioning

Adds a filter that will transform old json request into the latest version so that we internally only have to use one version. The old version can be used by using the accept header of application/vnd.aerogear.v`version`+json for now I have one example of this for the sender.

It uses json diff patch merge to change the incoming json request and additionally can have a dynamic class invoked as well.
should we tie that to a specific endpoint ?