- it was originally added in https://github.com/spesmilo/electrum/pull/1334,
with the goal of simplifying running the tests on local dev machines.
However this usage is not documented anywhere, and AFAIK regular contributors
don't use it either.
- tox just adds another layer of abstraction that is not that useful IMO
- I want more control over which electrum-deps are installed, which tox is
(in this case) unhelpfully abstracting away
