Getting it working with mod_pagespeed (r3061).

Updating trunk-tracking to compile and work with mod_pagespeed svn revision 3061 with 2 small modifications to serf_url_async_fetcher.cc to disable SERF_HTTPS_FETCHING.

Please note that anyone building mod_pagespeed from source will need to
a) edit serf_url_async_fetcher.h to change the line "#define SERF_HTTPS_FETCHING 1" to have 0.
b) edit serf_url_async_fetcher.cc to move the definition of "apr_status_t status = APR_SUCCESS;" on line 265 to be inside the "#if SERF_HTTPS_FETCHING" block (in order to avoid a compilation error for psol/mod_pagespeed).

Highlights of this change:

1) Propagating renaming changes related to
  a) Furious -> Experiment
  b) ModPagespeed -> PageSpeed.
2) UrlPollableAsyncFetcher going away.
3) RewriteOptions now requiring a ThreadSystem parameter for construction.
4) Removing client_property_cache references and usages (since this was removed from mod_pagespeed).
5) Propagating beacon construction changes (where POST requests can now carry the url query param in the request).
6) General fixes for API/test breakages in statistics_logger, fallback property page cache,
Merge pull request #396 from pagespeed/anupama-update-trunk-tracking

Getting it working with mod_pagespeed (r3061).