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 would ask you to please seriously consider the following changes which I think will make this file much simpler and more robust as it pushes more work back to ThaliClientToDeviceHubUtilities and so will naturally benefit this file as changes are made.

Step 1 - Delete lines 64-71 of this file and the RetrieveServerPublicKey and PrepareClientPublicKey methods
Step 2 - In the constructor please call GetLocalCouchDbInstance and then take the response and call getConnection, this will return you a httpClient configured to the local thali device hub.
Step 3 - Store that httpClient in a class variable
Step 4 - Delete lines 128-140.
Step 5 - Just use the httpClient you saved in the properly in line 148.