Test the order of sessions on the course manager

Sessions should be sortable by date and by offering time.
Switch to change event for ILM checkbox

Switch from click to change event so that we can test the sessions page.
Added test for #475
Sort ILM sessions by date on the course manager

Updated session_model.js to recognize ILM sessions as being different
from other session types which resolves #475

Pulled a commented out if/else out of course_manager_session-dom.js
Merge pull request #607 from jrjohnson/475-ilmsort

Sessions sort by date in course manager