Payment/Shopping Cart Backend

Add in CyberSource integration and a new VerifiedCertificate order item.

Doesn't have any tests as of yet. I wanted to collect any code review feedback while I work on them.

@ormsbee?

@jbau: Since we're on a tight deadline, we're just going to be making our own modifications on top of your code. Please feel free to make comments on this pull request.