Remove draper from Role, Roles, and RoleAppointment presenters

Made RolesPresenter extend the CollectionDecorator, which is sort of interesting.
Remove draper from PersonPresenter
Remove draper from the Promotional Feature presenters
Remove draper from featured edition presenter

Only used in Topical Events controller, is this a candidate for removal?
Remove draper from feature list presenter

The last one!
Remove Draper's vestigial tale from our tests
Remove redundant initialize method
Extract delegate_instance_methods_of and make it more configurable

So we can use it in the collection decorator and document filter presenter.

In passing we also stop delegating to_json in favour of as_json, it's a minor thing, but delegating as_json but not to_json will probably mean we end up doing The Right Thing and can safely do what we're supposed to and just implement our own as_json in presenters (much like we would implement our own as_json in a model, but not to_json).
Remove rspec from cucumber steps

Draper was pulling it in, and now it's gone.  We shouldn't be using it anyway.