Add httpserver to contrib

.. see http://stefanfrings.de/qtwebapp/index-en.html

.. this is a lightweight web server to allow GC to
   provide webservices.

.. we will be providing web services on localhost to
   enable R integration.

.. we will use web services to standardise the
   interface to provide something we can use in R
   but also anything else at a later date.

.. gcconfig.pri contains $$HTPATH that points to
   the location of the code, if it is not set then
   the web server is not compiled in.

httpserver/httprequesthandler.cpp

@@ -0,0 +1,19 @@
+/**
+  @file
+  @author Stefan Frings
+*/
+
+#include "httprequesthandler.h"
+
+HttpRequestHandler::HttpRequestHandler(QObject* parent)
+    : QObject(parent)
+{}
+
+HttpRequestHandler::~HttpRequestHandler() {}
+
+void HttpRequestHandler::service(HttpRequest& request, HttpResponse& response) {
+    qCritical("HttpRequestHandler: you need to override the service() function");
+    qDebug("HttpRequestHandler: request=%s %s %s",request.getMethod().data(),request.getPath().data(),request.getVersion().data());
+    response.setStatus(501,"not implemented");
+    response.write("501 not implemented",true);
+}