Rerun of Pairings

Sorry guys, I was trying to see if I could use the marshal module to do my serialisation instead of pickle, but it corrupted a few bots from each pairings dict so I quickly changed it back. I'm not sure why it had these issues since I tested locally on the dev server and it worked fine, but anyway it is fixed now, and was a completely different issue to what happened before.

It did hit the quota last night, so perhaps tone down the clients a little. There's a threshold below which it is cheap to run, but as the load increases I start leaving the free quota for the instances as well (not just database writes), which gets expensive much more quickly.