Remove use of the word "category", it's confusing, split up the two traversal tests
Hierarchies have tags and a standards filter

Part of #11

At this point, I think they're ready to begin being integrated,
We'll still need to:
* Add these to the timeline (I think persistence should "just work")
* Regenerate them from the standards organization so they are included in the standards.json
* Integrate them into the website.