Instead of documenting Puppet classes using `ClassObject`, use a custom
subclass of `NamespaceObject`. This is done because Puppet classes are not Ruby
classes and will have components that don't fit into the model offered by
`ClassObject`.
This commit also adds a couple of monkey patches to integrate the new
`:hostclass` into YARD tooling and the beginnings of some custom templating.
The YARD plugin is currently architected using `require_relative` so that it
can be loaded outside of Puppet. Unfortunately, `require_relative` first
appeared in Ruby 1.9.1.
Achieve compatibility using the Backports gem.
Charlie Sharpsteen