This saves something like 15ms on our 1000 message get_old_messages
queries, and will save even more when we start sending JSON dumps into
our memcached system.
We need to install python-ujson on servers and dev instances before
pushing this to prod.
(imported from commit 373690b7c056d00d2299a7588a33f025104bfbca)
See PEP 328[1] for details. This feature was introduced in Python 2.5 and
will become mandatory in Python 3.
[1]: http://www.python.org/dev/peps/pep-0328
(imported from commit 7444eeba8a08d5f91b94c7921848f2274979bd76)
Tim Abbott
Luke Faraone