Adds support for configuring multiple aliases on the adapter

I need support for multiple aliases for the same record on the adapter, as I have some models that are loaded with different names both from the same 'parent' and from different 'parent' models. This is partially supported, as you can set the ```inverse``` option on an association, but it there is no support for multiple aliases, so I find it lacking.

This adds a new key on the model configure ```aliases``` which takes an array of aliases and sets them the same way as the ```alias``` is set.