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....
I don't understand why the request body is being turned into a string. We don't seem to do anything with it other than pass it on to the request.

So can you please use the getInputStream method on the session object to get an input stream and then use it to create an Apache InputStreamEntity which you can then pass into the BasicHttpEntityEnclosingRequest? This should let you get rid of the parseRequestBody method all together.

Or did I miss something?