Xml example: Route53 client

This builds on issue #225 and satisfies issue #193, showing how to write a client which demarshals xml.  I've used SAX in this example as it is very portable across android and java.  This example currently lists domains in Amazon Route53.

Once issue #223 is complete in a way that we can read the entire http request (method, headers, query, everything!), I can rewrite this to be an Amazon S3 example.