Remove reek gem dependency temporarily
Change self.included to be private

* The method is private within Module, and I like to respect the
  method visibility same-named methods in ancestors.
Merge branch 'master' into devtools

Conflicts:
	Gemfile
Fix AbstractType::ClassMethods#abstract_method spec to kill mutation
Fix AbstractType::ClassMethods#abstract_singleton_method spec to kill mutation
Add spec for AbstractType.included to kill mutation