Documentation of histogram methods

[jpivarski]

I've moved the issue here from scikit-hep/uproot3#193. It could be part of a long README, a Binder notebook, a wiki, or REsT for uproot-methods.readthedocs.org; I'm not sure. Ideas, @HDembinski?

[HDembinski]

I like READMEs with some minimal kick-start examples, and then a link to a full-blown tutorial. For a full-blown tutorial, a Binder notebook is the nicest solution, I guess.

[HDembinski]

The idea of the README in my view is to throw a bone to the unsure potential user, who is taking quick looks into a few similar libraries and will stick to the one which seems simplest to use.
For uproot-methods, you could argue that it is already a technical package, which you will only look into when you already decided to go for uproot. So maybe the bone throwing is not necessary here (which is why I would have preferred to have it in the readme of uproot).