Add mod_serf.dsp at last, based on the patch available in;

  http://people.apache.org/~wrowe/fixserf-win32-0.3.0.patch
although there is trouble here, and pollset troubleshooting ahead.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@906327 13f79535-47bb-0310-9956-ffa450edef68