1.0 release prep

This branch represents a series of refactors to `omnibus` to prepare it for the impending 1.0 release to rubygems.org. Highlights include:

* Full YARD documentation
* Full `omnibus` CLI and hiding of underlying Rake
* Projector generator for creating skeletal Omnibus projects which includes a full Vagrant 1.1 build lab.
* Omnibus cookbook (and it's dependencies) now live externally: https://github.com/opscode-cookbooks/omnibus
* Omnibus config file is now `mixlib-config` based.