(Work in progress) LMS badges

1. Display a preview of students' badges beneath the progress graph, with link to the page in 2.
2. Display details about students' badges in a new separate page of the courseware.
3. Display all of the badges a student has earned across edX in a dashboard-like separate page.
4. Allow a tab called "Badges" to be added, which links to the page in 2.
[Screenshots.](https://edx-wiki.atlassian.net/wiki/display/~dkh/LMS+integration)

Has no actual effect until the badge service is finished and deployed.

Currently very much a work in progress; code review appreciated.