Feature/create tmpdir for user on

Previous incarnations of the PR were screwed up due to mismanagement of multiple topic branches while working on multiple independent changes at once. This time the PR is coming directly from a feature branch.
How would you feel about error-checking the host.puppet call and providing a useful error message indicating that the 'user' parameter must be specified if puppet is not installed?

I guess it should also handle the error case when the specified user does not exist on the given host.