Allow behaviors to be added for baked models

If you bake a tree model (actsAs Tree) and you got lft/rgt/parent fields bake should be able to auto-detect this.

Derived from tryouts back in 2011 - see https://cakephp.lighthouseapp.com/projects/42648/tickets/1781-plugin-information-gets-lost-during-baking

Can then be further enhanced to also support plugin behaviors (Sluggable for slugged field etc). This can than done via custom bake task that extends the core task and just overwrites the method. Easy to extend and enhance in user land code.