Major refactor of #chef_role and #chef_search and ChefZero tests

This PR includes major refactoring and testing of #chef_role and #chef_search. It also resolves issue gofullstack/capistrano-chef#25.

Specifically (from commit message)...

* Upgrade chef and capistrano gems
* Refactor #chef_role so that normal and block based querying work
* Better support for customization via dependency injecting Search class
* chef-zero backed test units and environment
* Proper Gemfile and Rakefile
* Rake::TestTask verbosity is optional

Now that I see PR #27 it would also fit perfectly with this setup.

I have more things I need and can contribute but I'd like to get this into the gem so I can use it. :)