Changes to the reveal.js dependency

[hectorsector]

The template repo relies on reveal.js. At the time we created this course, the only way to utilize reveal.js was through a submodule.

As of earlier today, the submodule was checked out to a 2017 commit, so I did I tried to make this a little easier today.

Today, here are the changes implemented:

• We now consume reveal.js via its Node module
• We no longer use the reveal.js submodule
• Because we rely on GitHub Pages for static hosting, we reference files in the node_modules folder directly

I'll close this out in a couple of days but thought it was worth explaining for folks that might come in behind me trying to make changes to this course.

[lmkeston]

Seems to be working properly!