Installation notes and docs

[phockett]

Needs doing! Much of this is now relatively mature (at least in terms of local use), but needs consolidating and documenting properly.

[phockett]

Basic demos and docs in places as of 0f4f7d6

See

• /demos for notebooks,
• HTML versions and API in /docs and via ReadTheDocs, https://epsman.readthedocs.io

So far only covers job setup stages, and only restructure160221 branch