Since we don't want the name of the tool to reflect the fact that
it is using yard internally (this is an implementation detail), rename
the face to `strings`. Now when one wishes to generate documentation,
`puppet strings` will be used rather than `puppet yardoc`.
In order to make the code more readable, separate the tests into
different files for each handler. Additionally, extract the helper
methods into a separate module which may be included as needed.