Add recipes to install the MeetMe Plugin Agent

* Borrows heavily from flinc-chef/newrelic-ng
* Berks-ified!
* Make better use of `['newrelic']['config_path']` attribute
* Update README to explain new attributes
* Remove unnecessary tests
* Rename Plugin Agent recipes to be consistent w/ rest of cookbook
Clean up README
Add tests for PHP Agent, Server Monitor, Repository recipes
Switch `recommends` to `depends` to ensure cookbook converges via berks

Using `recommends` does not work when converging using berks &
Vagrant. The `ms_dotnet4` dependency is left alone, as we're not
currently testing it via berks/Vagrant/kitchen