Implement Debian-ish get_packages

I also included a ##TODO stub for RHEL-ish yum-based systems. Basically, he does what he can with what he finds.

One issue I have with this snippet is I wasn't sure if the die statement was the correct way to deal with a system that doesn't have yum nor dpkg... But that's fodder for future dev. One other major issue is that it only works on the local system -- we still need to implement the remote_run functionality. Again, future commit work.

The first commit is just adding some ##TODO hooks and commenting some of your code to make it slightly clearer in my head what is being done and why. May not be helpful to anyone else, but I feel better about it. :)