initial commit of shopping cart and cybersource integration
added shopping cart list template, embedded form
add parameterization of cybersource creds
Move shopping cart from session into model/db
add Validation function for cybersource receipt POST
add Order model fields for receipt generation
factor out cybersource processor from cart
Lots more verification of CyberSource reply + receipt generation
about page changes, refactor processor reply handling
Add in new VerifiedCertificate order item
Pull CyberSource values from environment variables
when in a dev environment.
Remove enrollment_cost from course_module
Some cleanup fixes to get verified certs working.
Put shopping cart views behind flags