initial version of a rest api

- a scaffold for the rest api, implemented using spray, following the style of http://typesafe.com/activator/template/activator-akka-spray
- much more to do in terms of configurables and functionality but I want to get this in now so others can join :smile:
- oh, and to launch, just say "run restapi"
- try it out:

      curl -X GET http://localhost:8001/status
      curl -X GET http://localhost:8001/demultiplex/FLOWCELL
 
I'm undecided if we should keep this in here. I keep adding it when debugging - so maybe we can keep it around but add a TODO message there to keep us alert that it should be removed in the future?