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....
Totally agree, hadn't had to chance to come up with the right option yet - your suggestions make sense.  I'm inclined to use #2 over a non-standard verb as it will just make the JS much cleaner once there are several of these (e.g.  $.getJson(...) instead of $.ajax({.,.,})