Add ability to examine extensions.
Introduce a Base class to clean things up a bit.
Make sure tables are returned in alphabetical order.
Use pg_get_expr() to get a better representation of default column values.
Make it easier to examine ad-hoc db structures in specs.
Introduce the concept of result equivalency, and make sure it works for the basic case of current and dropped columns.
Cover more equivalency cases, including column types and defaults.
Add some notes on system tables and columns.