consolidate kitchen suites and expand coverage
fix whitespace issues in `pg_user` definition
fix a few issues with database extensions:

* ensure that the `contrib` recipe is included if
  extensions are being installed
* properly handle quoting, and non-quoting, of 
  extension names
skip `postgis` on debian for now:

* PostGIS support on debian is complicated at the
  moment. I'm deferring this until I have more 
  time to spend on it.
Merge pull request #77 from phlipper/regression-test-coverage

add regression test coverage