Remove unused var and always return self in _addInstances for consistency
Remove unused var and always return self in _addInstances for consistency

jballant/backbone-base-and-form-view,antialias/backbone-base-and-form-view,jballant/backbone-base-and-form-view,antialias/backbone-base-and-form-view,1stdibs/backbone-base-and-form-view,1stdibs/backbone-base-and-form-view,robrichard/backbone-base-and-form-view