adds basic kitchen tests for postgresql cookbook
add initial Test Kitchen integration tests:

* replace initial `bats` setup with `serverspec`
  framework
* add ubuntu-(12|13).04, debian-(6|7) platforms 
* add `default` suite
* add `server` suite with a basic `default_server`
  smoke test
* run with vagrant locally and ec2 on Travis CI
cleanup supporting bundler configuration
simplify `.kitchen.yml` for now:

* only use vagrant locally, skip on CI for now
  until a better long-term solution is available
Merge pull request #67 from phlipper/kitchen_tests

Initial `test-kitchen` suites

closes #65