Relay prototype

Considering getting this simple relay implementation into ThaliProject while I finish up the other aspects of it - to simplify folks using the HTML5 seed.   Perhaps into a new branch on ThaliProject - but then you wouldn't be able to see the diff for review.

Only one source file here for the relay - RelayWebServer.java (and RelayWebServerTest.java).  The other bits are all NanoHTTPD.  Open questions on code file headers for those....
They never seem to have it - it is parsed off the request directly into these maps.  Looking at the simple way it is implemented it should work regardless though, the URI and QueryString bits are just either side of the ?, and if a fragment is in either place it shouldn't get lost.