SUMO is on Python 2.7!

[Michael Cooper]

We just got done deploying the 2.7 branch to production! Thanks to jakem
for the server side work to get us Python 2.7 and related tools.

It didn't go quite as planned. We tried to pull two webnodes out of
rotation and update them, and the swap and do the other two. Unfortunately,
when we deployed to the two out-of-rotation nodes, somehow the two
in-rotation nodes got a partial update, and started breaking on
dependencies. We aren't quite sure what happened there, but we pushed on
and updated all the nodes and pushed them all in to production. We had a
few minutes of downtime unfortunately, but now everything is good.

So what's this mean? Travis is now running both Python 2.6 and 2.7 tests.
2.6 tests are marked as "optional", so if they fail Travis won't complain.
Next we need to go update our documentation and scripts to make sure they
all say 2.7. I'll file a PR for this sometime soon.

As of now, Kitsune doesn't support Python 2.6 anymore. It still works
because I haven't broken anything, but that won't last. Please update your
dev environments to use 2.7 if you haven't already. Feel free to use 2.7
libraries and syntax that wasn't available in 2.6.

Yay!
-mythmon