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
Temporarily disable Save All Draft button

While #609 is unresolved don’t ever enable the Save all as Draft
button.  Place some explanatory text in the title to inform users of
why the button is disabled.  Also in case I missed anywhere this button
would be enabled I replaced the action on click with another warning
message.