Working example of database object re-structuring.

This change is not fully implemented, I still have to finish the postgres, and mysql wrappers.

@sbbowers what are you thoughts on the over all structure. I tried to simplify what I previously had.

We dropped the vendor parent class, and moved all the database wrappers into their own name space. I also tried to remove as much logic as I could from the wrapper, and have them only the the core set of functionality required.

I still have to add an escaping function into the db wrapper objects.

I also have to update the model class to use the new object.

This change would remove the Db and Database classes (and their sub classes, and replace them with new objects. The external interface should be about the same.

Let me know if I should continue updating the db wrapper classes, of if you want to take the DB objects a different direction. 

BTW, I did keep the DB pool logic, and re-integrated it into the Db class, but I stopped supporting async db queries. I also removed support for any database fetching other than associative arrays.