adding back the "old" grade upload page
Some warnings and clarification about multiple grade entry methods
Link to Angular course grade entry/uplod page
Revert "adding back the "old" grade upload page"; obsoleted by Angular

This reverts commit f60e391c34d53e440d78573b908c049f83a2c4e6.
CourseSections have grades; Courses don't
Merge branch 'master' into develop