console: support /pagespeed_console

sligocki is adding a feature to pagespeed where it will parse your statistics
for you and determine if there are any problems.  This CL wires up the
ConsoleHandler and also includes a few required files in the build process.

It doesn't work yet, because as of svn r3193 the console has a hardcoded json
request to '/mod_pagespeed_statistics' and in nginx we use '/ngx_...' .
I've tested this by changing all uses here to use the "mod_..." version and that
worked, but I've undone those changes.

scripts/prepare_psol.sh

@@ -63,6 +63,8 @@ rsync -arvz "$MOD_PAGESPEED_SRC/" "psol/include/" --prune-empty-dirs \
   --include="apr_memcache2.c" \
   --include="loopback_route_fetcher.cc" \
   --include="add_headers_fetcher.cc" \
+  --include="console_css_out.cc" \
+  --include="console_out.cc" \
   --include="dense_hash_map" \
   --include="dense_hash_set" \
   --include="sparse_hash_map" \