Improve course sidebar.

[IlIllII]

What has been done

I've implemented a sidebar to overlay on the digraph. When you hover over a course in the sidebar the node associated with it in the digraph reacts as if you've hovered over the node itself. Additionally, I color coded the courses listed in the sidebar similar to the nodes, making it easy to discern courses by subtopic.

What still needs work

I think it looks kind of bad randomly colored as it is. I suspect it might benefit from being organized into logical subtopics, similar to how you might see courses organized in a university course catalog.

We can change the structure of the data to facilitate this process. I may have to add a numbering system so it is easy to topologically sort courses into a logical sequence within subtopics.

To do

Clean up the sidebar and make it easier to parse visually, possibly incorporating the ideas mentioned above.