Can't install tohil through pip via the VCS url #47
Description
Though not generally used for production purposes, it can be useful to install Python packages from VCS repos through pip by using a special URL (documentation: https://pip.pypa.io/en/stable/cli/pip_install/#vcs-support). Tohil cannot be installed this way because it does not have a setup.py file in its repo. Instead, setup.py is generated from setup.py.in via autoconf. We should consider not dynamically generating the setup.py file so that this installation method is available.
This would be less of an issue if tohil were available via PyPI.