--------------------
* Update branch name master -> main in agreement with
https://github.com/github/renaming (#406).
* Notebook improvements:
* Add ground truth to noise notebook.
* Rename notebook "quickstart" -> "model_selection".
* Split notebook tests in 2, extend, reduce test matrix (python 3.7).
* Improve output at the beginning and end (e.g. no `end_time` at beginning;
show duration).
* Add walltime plots (`plot_total_walltime`, `plot_walltime`,
`plot_eps_walltime`).
* Make sure `ABCSMC.run()` is always properly finished (sampler, history)
by a wrapper (all 401).
* Redis sampler with look-ahead mode:
* Fix insufficient logging of look-ahead samples.
* Log all accepted particles.
* Add `plot_lookahead_...` plots for look-ahead mode diagnostics.
* Add global figure parameter settings for pyABC (all 405).