Postgres 9.4 Jsonb support

This patchset adds support for jsonb in the forthcoming Postgresql 9.4 release (currently in beta).

It correctly marshals the json data to and from the database, as well as adding support for the ? (has_key) and @> (contains) operators.

Tests are included and passing.
same here, these tests work for JSON too ?   should use the same tests on both