First draft at a skeleton framework for rspec-system-puppet tests.
Add checks to ensure the service is running.
WIP
A fairly big restructuring.  First I've moved all the OS specific
stuff into a .yaml file so we can reuse it between different tests
without repeating ourselves, and then I've converted class_spec.rb
to using it.

It's not perfect but it's a lot cleaner than a giant if/else/ tree.
Fix path on centos.
Merge pull request #207 from apenney/systemspecs

Initial draft of rspec-system testing