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.
Use `require_relative` for all components under Puppetx. This makes it possible
to load `pupetx/yardoc/yard/plugin` outside of Puppet as a YARD plugin.
Also fix the `yardoc` face so that Puppetx bits are loaded _after_ feature
checks.
Charlie Sharpsteen