Persistent commercial ab test

This sets up a persistent ab test, for the commercial component. As we're sending the ab test segment to DFP, they can now use that as a targeting hook, e.g. show a different component if they're in the test or not

So not a true ab test, but allows us to get the benefits of it, i.e. remember what test you're in, pass the segment on to omniture, etc 
Maybe put a lareg comment at the top of this file or next to the expiry here stating why it's got such a long date.

It does also open the debate as to whether we should have type of permanent test, like with our switches.