Simple bug fix for _destroyed.

Previously _destroyed was trying to remove _idOf(model), which is
returning this.name + model.id. However from what I can tell this.records is
just the model.ids, non of which have this.name concated onto the front.
Hence the id names were not being removed from this.records.

I have also updated the minified version with this change.

Sorry if this turns out to not be a bug and a misunderstanding on my end, its seems to be working correctly from what I can tell!