Add ensureBehaviors() to detachBehavior*()

Need to add ensureBehaviors() to detachBehavior*().

The intent may be to detach behaviors defined in behaviors().
In the original implementation, if these behaviors() are not yet attached, they can not selectively be detached.
Merge pull request #136 from mdeweerd/patch-1

Add ensureBehaviors() to detachBehavior*()
Rollback word consistencty over entire codebase (ref. #139).
Merge branch 'master' of github.com:yiisoft/yii2
Fixes issue #134
Merge http://github.com/yiisoft/yii2

* http://github.com/yiisoft/yii2:
  Fixes issue #134
  Rollback word consistencty over entire codebase (ref. #139).
  Add ensureBehaviors() to detachBehavior*()