Highlight sections on course hover

[chrisnicollo]

Addresses part of https://github.com/ufosc/SwampScheduler/issues/29.

Make it so when courses are hovered on the left, sections in the middle are highlighted. I can add functionality to highlight sections on section hover in this branch later using a similar pattern.

[chrisnicollo]

Also I converted SectionDisplay to a functional component

[RobertConde]

This is great work! Let me know when you want me to actually review it for a merge. :))

[RobertConde]

OMG I just checked out your changes.

I am sooooo pleased!!! It's so responsive, I love it!!!!

[RobertConde]

Only one bug. When I move from one section to another in the middle column all of the sections don't stay highlighted. Maybe it was a bug introduced in the debouncing.

[chrisnicollo]

I've tried to use redux for message dispatching on this branch, but I've no clue if the code works because locally I'm getting dependency issues where redux cannot resolve references to react