Update test-kitchen support

* Removes the old "test cookbook" (functionality covered by suites in
  .kitchen.yml)
* requires vagrant 1.1, test kitchen 1.0.0.alpha.4
* Removes vagrantfile (now handled by kitchen-vagrant 0.7.4+)
* Add TESTING.md doc
Merge branch 'test-kitchen-1.0'
Use postgresql string as service name.

The minitest service assertion does not appear to use the status
command for the service, instead falling back to process table
inspection.
release v2.4.0
increment version for development