[JRO] Removing specs for deprecated feature
[JRO] Big refactor of decorator code.

Blew up, and out, a large hunk of the decorator code so that
topics and private topics were sufficiently isolated with regard to the decorator responsibilities. This turned into a domino effect where changes 

* Extract common decorator code into a base topic
  decorator and compose the vanilla and private topic
  decorators using that base decorator
* More proper use of the SimpleDelegator class
* Pull up the Chronic timezone change to the spec
  helper instead of before every test using Chronic.
[JRO] Use PG instead of SQLite

* Use database_cleaner
* Tune the database_cleaner stuff in spec_helper