Fix for #209 and assorted enhancements.

A few minor enhancements to `setup.py`:

- A fix for #209.
- Do not print the configuration when an unknown command was given.
- Removed `help` and `version` commands. IMHO it is confusing to have this functionality both as command _and_ as options. Let me know if you'd like to keep those so that I can rebase the pull request without those changes.

The individual changes are split up into separate, self-contained commits.