Taxonomy class to make use of interface models.

[chriscalip]

Who wants it? Can we have it?

Lets have a looser coupling of Taxonomy dependencies. From concrete models Devfactory\Taxonomy\Models\Vocabulary and Devfactory\Taxonomy\Models\Term to contract/interfaces/

Why want it? so App can add additional attributes to the models or additional behaviours.

[markcameron]

It's a good idea, but at the moment you can just extend one of the models to add in extra functionality if needed. I don't have time to work on this, and ideally it could probably use a full rewrite for a new major version.