Make type check for self.code a little more robust, give default val for mmlans so it's never undefined

lms - pearson: styled return to exam link on timer and revised timer positioning to not interfere with main course nav

This reverts commit 66889b87, reversing
changes made to 0dd9c24e.

This was merged too early--it's still missing the filtering and display-your-cohort changes.
Will need to revert this revert later.

This reverts commit 965e3b4c, reversing
changes made to 1a7d2a06.

I accidentally merged this before it was ready.  This was silly, so now I'm undoing it.  We'll need to revert the revert later.

Switch timed_module to store location, and use to navigate from timer when timer displays on non-exam course pages.

make LMS forum subsystem more robust in case of orphaned discussion modules. Given our draft/non-draft duality, we don't currently have a means to always do proper housekeeping at this point in time. However, we have to stop the LMS Forums from blowing up when encoutering one of these.

a model change as well)

This reverts commit 05354745.

This reverts commit e7450874.