Implemented course details and listing.

NEW
* Created preliminary course details view. Still some more stuff to
  be done to clean up the presentation.
* Created the course listings view; fairly basic.
* Created preliminary course sequence view, remains unfinished for
  now in order to refocus priorities.

CHANGES
* Fixed foreign key name reference for CourseTimeslots and CourseSection.
* Added `code` attribute to the course_timeslots table.