Update param types for addRegion method

@thejameskyle LMK if this is correct
Completely agree. We need a way of differentiating between an instance of a class and the class itself.

Right now dox does not support param types, but I think i'm going to pull this [pr](https://github.com/visionmedia/dox/pull/84/files) in and start using it to get better data. With that said, we should choose the most appropriate convention from here: http://usejsdoc.org/tags-type.html