Service improvements and example

This pretty huge pull request lands:

* `Service` and `NetworkService` base classes for services
* `HelloWorldService` example service
* A basic implementation of module groups
* Some inspector changes to accommodate groups

Here is an example of some `HelloWorldService`s, two of which are in a module group (the `config.rb` responsible for this is on the right):

![Screenshot of features from this PRQ](https://cloud.githubusercontent.com/assets/374963/4089615/842b8032-2f6f-11e4-923b-e3a49a52d230.png)