RLS: Regression tests
RLS: Enforce row-security on COPY
RLS: Tests for COPY support
RLS: Supplimental docs
RLS: Update and tidy up documentation
RLS: Add FAILING tests for SECURITY DEFINER in RLS

See 52689207.4060605@2ndquadrant.com
RLS: Add FAILING tests to demonstrate problem with FK constraints and superuser exemption