Drush 3.x

I'm doing this more as an exercise to make sure I'm successful at the process we're outlining here http://www.newmediadenver.com/node/83. That said, I did notice a drush chef cookbook (https://github.com/msonnabaum/chef-drush) that we might want to leverage instead of using our own. Or we can make ours simply test the state of drush versus deploy it.

Still to add to this pull request is integration tests. But I wanted to pause here first for feedback before proceeding.