Specs for CHEF-3297. TDD rules.
New property :excluded_members for group resource and required common code around it.
Handle :excluded_members in dscl provider.
Support :excluded members in gpasswd provider.
Fix the error message in the conflicting user add/remove in group resource.
Support :excluded_members in windows group provider.
Better root checks and better naming for group account in functional group tests.
Merge pull request #1124 from opscode/group-core-and-macos

Core Group Provider + Dscl / Windows / Ubuntu providers changes for CHEF-3297