Move RavenDbServer to Raven.Database project.
New Embedded test that uses OwinEmbeddedHost and OwinHttpMessageHandler. Modify HttpJsonRequest/Factory to allow specifying of a HttpMessageHandler. Expose the 'embedded' client via property on RavenDbServer
Import OwinClientHandler, ResponseStream and fleshed out some tests for some more 'complex' http scenarios.
Fix TODO: recreate HttpClient will use specified hander