Reorganize examples, experiments, notebooks, etc. directories

[gully]

We currently have examples/, experiments/, tutorials, FAQ/, and notebooks/ directories. Many of those examples pre-dated our telluric emulator and new API, so they are somewhat stale now. Let's deprecate some content, take the useful stuff, and put it somewhere conspicuous.

I'm almost inclined to put everything into notebooks as "Case studies" following the awesome lead of the exoplanet case study gallery.