First pass at fixing broken notifications

Fixing some code I changed unecessarily

Removing TODOs which are not necessary
Adding unit test coverage and updating per github review

Conflicts:
	spec/unit/recipe_spec.rb
	spec/unit/resource_spec.rb
	spec/unit/run_context_spec.rb

Resolving cherry pick commit merge issues
Fixing homebrew package to use provider resolver per code review
Changelog for https://github.com/opscode/chef/pull/2621

Conflicts:
	CHANGELOG.md

Resolving more cherry-pick merge issues