Updated documentation for students.

Still need to finish, also need to add changes to Instructor Documentation, and clean up documentation text for drop out explanations of how-to's.
Updated one piece of documentation

Continuing documentation work.
Made one more addition.

Added documentation for checking final grade for students.  Students still appear to have no way to create a group from their dashboard.
Merge pull request #439 from bellotastudios/documentation

Documentation
Merge branch `master` into `dashboards`.