Stanford paid course registration

[jbau]

With tests, some settings changes
(all should default to not breaking anything for edx)

Added styling for shopping cart User Experience

• Styled shoppingcart list page
• Styled navigation shopping cart button
• Styled receipt page
• Styled course about page for shopping cart courses

@dianakhuang and @talbs for the styling/small bit of front-end.

rake coverage at 100%, rake quality at 100%

[jbau]

To give a bit of background context, we are going to be running this for Stanford Med School's Continuing Medical Education (CME) program. The students must pay in order to enroll in courses and access content.

To set the prices, we'll just create "honor" CourseModes with minimum prices, and use that to create PaidCourseRegistration cart item.

[jbau]

This might be the best place to start review? Basically the course_about page will have an "add-to-cart" button instead of a register button.

[talbs]

@jbau, thanks for the ping on this. I've chimed in on your front-end code, but would also love to see a local instance of this. Can you list out some simple steps to turn on the features needed and progress through the flows (in order to see all of the views you worked on)?

Thanks for the help and nice job getting this up and running.

[dianakhuang]

I know that this isn't part of this pull request, but I think part_of_order is a confusing name. contained_in_order? order_contains?