Use include instead of parameterized class when no params are given.

Instead of perpetuating the use of parameterized classes, which we do
not want to do in light of Puppet v3 with Hiera integration, this change
invites people to use 'include' instead of the parameterized class
syntax when no params are present.
Merge pull request #187 from ghoneycutt/style_for_class_with_no_params

Use include instead of parameterized class when no params are given.