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
It seems like we'll need this same code later, since we'll need to check for the primary section when we remove people from a section (say). Can we factor it out into a separate method so that we can reuse it?