Add a new handler for empowering special query

To fitler and sort in the empowering API the url is like:
https://api.empowering.cimne.com/v1/contracts/?where="dateStart"<"2013-10-11T16:37:05Z"
https://api.empowering.cimne.com/v1/contracts/?sort={"dateStart": -1}

This change permits use where and sort to the API