Popover shows when hovering course info box

--public

Prerequisite popover now shows up when you hover the course info box.

--end_public

Addresses #115 (closed) and #177 (closed)

• Prerequisite popover now shows up when you hover the course info box.
• Remade, renamed, and moved the Alert test to test the CourseInfoBox component instead (which is the parent of the AlertInfo component).
• Schedule header is more responsive and header info area has more width to work with.