Make it clear which materials to use

[choldgraf]

I think it's great that there are multiple versions of some materials in here, but it's also confusing which one is the "default" or "preferred" one to use. I think that having a single copy of things might be the most maintainable and clear way to move forward. For example, there is a set of "instructor instructions" to introduce the notebook, but somebody has also created a RISE-ready notebook as well. We should just have one of these (my pref is for the RISE notebook).