Utilize ORM drivers for database engine independence.

+ Use ORM database drivers to avoid writing mysql/postgres specific SQL.
+ Use ORM driver helpers to escape sql queries.
+ Run test suite against both postgres & mysql.
+ Connection pool support!
+ Update readme

What we currently call a `connection` is now actually a `driver`, however this change is big enough as it is, so I left it be.

It is possible to avoid writing raw SQL altogether by utilizing [connection.query](https://github.com/dresende/node-sql-query) however it's not currently necessary as the SQL code is platform agnostic enough as is to run on all currently targeted platforms.