Adds the nextRow function.
Instead of openStmt/openStmt_, use openStmt and withBind.
Renames openStmt/closeStmt to openStatement/closeStatement.
Uses bind instead of withBind.
Adds a test for withStatement_.
Adds test for withStatement_.
Removes the row number from Row.

This lets us offer a cleaner API for nextRow. Additonally, we can now turn Row
into a simple newtype.