Fix wc compatibility for BSD / OS X & idempotentify docker network create
Fix compatibility on BSD / OS X of comparison of wc output in makefile by stripping whitespace.
Idempotentify docker network create to avoid big ugly error message.
Also fix slight spelling mistake.
Part of #113 (closed).
This is a fixup of !158 (closed) with squashed / fixedup commit history (also better explanation). It's rebased on recent master and the branch is here on the main repo allowing CI to run. Credit goes to @tias77.