add inheritance to lower layer meta model

[deanhiller]

To keep more like an RDBMS, we did not store meta information on inheritance. This was a big mistake. We need to revisit this and store a DboTableMeta object for the superclass(which we already do) and store one for each subclass as well. This will allow the command line tool and ORM layer to play nicely together where

1. we can select * from Civic which gives us all Civics using a Civic only index
2. we can select * from Car which gives us all Civics, Accords, etc. etc using the cassandra get all rows from CF
3. This allows us to not have to use the allRows method anymore and deprecate the allRows method completely in place of select * from XXXXX which would give us all rows.

This is not a high priority yet but eventually we need to get to it.