Fixed stack overflow when coercing mashes that contain ActiveSupport::HashWithIndifferentAccess values.
Merge branch 'numinit-mash-indifferent-access' into mash-indifferent-access

Conflicts:
	CHANGELOG.md
	Gemfile
	spec/hashie/extensions/coercion_spec.rb
	spec/hashie/extensions/indifferent_access_with_rails_hwia_spec.rb