Debian package for 0.2.1

Fixes #157.

Includes the latest bugfixes to the zpm code, as well the addition of the python-swiftclient dependency in the packaging. (python-swiftclient was a dep as far as the python code was concerned, but not in the package; this was a bug.)

This is a derivative of #160; it should land first for a clean diff.

Update: I have published this package to https://launchpad.net/~zerovm-ci/+archive/ubuntu/zerovm-stable/+packages. Please have a look and test it.