Add support for debian and centos.

I have reforked and added support for debian or centos by using the pip installation method for ansible.

re your [comment](https://github.com/protobox/protobox/pull/61#issuecomment-35902345) on my initial and quite horrible attempt at this pull request the first time

I don't believe that it will be an issue with security, maybe if it does become an issue, you can modify this to run every time, or update/upgrade every time.

Also an option is to pin the install and use https://github.com/nvie/pip-tools instead, but this is a start.