Primary section 

Summary of changes:

(1) Add logic to determine the primary section.  If the sis_section_id matches the course_instance_id, this section name is considered the primary section and will appear at the top of the list

(2) Code cleanup, remove unused code and reduce the length of the lines to under 80
Yes, this account for cross-listed courses.  What is coming later, probably as another story/task is the "secondary" sorting, which the sections that contain sis ids, appear before the non-sis ids.