Merge pull request #55 from larsbutler/posargs-for-pytest

Add {posargs} for tox test run config
setup: use setuptools over distutils

Distutils is the stdlib packaging tool. However, setuptools is the
preferred tool for projects that define dependencies:

  https://python-packaging-user-guide.readthedocs.org/en/latest/current.html

Setuptools is a dependency of virtualenv and pip, so most developers
will have it installed.

Using setuptools means that the dependencies will be automatically
installed when running 'python setup.py install'. This is important
for the Read The Docs build since it installs the project like that
instead of using pip.

If setuptools is not present, a warning is printed and the
installation/packaging can continue.
Merge pull request #56 from mgeisler/setuptools

setup: use setuptools over distutils
Add zvm megascript

This adds a `zvm` command line executable which simply glues `zpm` and
`zvsh` together into a single script, with a unified set of commands.

`zpm` subcommands are imported verbatim and can be run in the manner of
`zvm new`, `zvm bundle`, etc. `zvsh` command args have been placed
underneath the `zvm run` subcommand, but have otherwise not been
changed.