Option to allow save() and delete()

[motin]

Useful when wanting to edit active record attributes using generated CRUD during rapid prototyping and in general when the developer understands the risks but still wants to use save() and delete() methods directly

[samdark]

@creocoder please review.

[creocoder]

Its designed by other way and its strange to hack design by adding such property. Btw https://github.com/creocoder/yii2-nested-sets designed to use save and delete directly. There is no plans to add such functionality to Yii 1 version.