Fixes #5: Added `TaggableBehavior::tagNamesAsArray` boolean property, added `TaggableBehavior::getTagNames` boolean param asArray, `TaggableBehavior` refactored.
Fixes #5: Added `TaggableBehavior::tagNamesAsArray` boolean property, added `TaggableBehavior::getTagNames` boolean param asArray, `TaggableBehavior` refactored.

hdushku/yii2-taggable,creocoder/yii2-taggable