Added bc to the core packages list since we use it to compare version numbers inside of bash deploy scripts.
Handle setting up the root user on machines where the inital SSH user has a password set.

Apparently the Canonical EC2 AMIs don't have a password set for the ubuntu user by default, so there was no need to prompt for a sudo password.  Prompting for the sudo password was broken because we needed the inital SSH user's password, not the deploying user's password.
Added a generic cloud provider for using rubber with physical hardware, virtual machines, or otherwise unsupported cloud providers.
Merge branch 'add_generic_provider'