WIP:  Content Experiments Documentation

See draft documentation at:  http://draft-nested-components.readthedocs.org/en/latest/organizing_course.html#nested-components
s/b "In the **Display Name** field, enter a display name. This name is only used in Studio..."

(It's the same capitalization rule that applies in common nouns vs. titles: "Dr. Nagy is a professor at Harvard" vs. "Professor Nagy teaches at Harvard.")