Add setup.py
Add tox.ini and test-requirements.txt
Add 'cover' environment to tox

'cover' allows one to run test coverage reports on zpm code.
tox.ini: update references to zpmlib

This package was renamed from zpm to zpmlib.
Merge pull request #12 from larsbutler/test-scaffolding

Test scaffolding
Add debian packaging artifacts
Add packaging instructions to README.md