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....
Hum.... this worries me. The reason is that @BeforeClass and @AfterClass are only supported in Junit4 and Android only supports Junit3. The reason the tests work anyway, I suspect, is that the bug I linked to above DOES NOT exist in Android, only Java.

But this is WAY too clever. Anyone working in the code is going to see '@BeforeClass' and '@AfterClass' and think they work everywhere and inevitably do the wrong thing. This feels too fragile to me. To have one behavior in Android and a totally different behavior in Java. 

What do you think?