Thread safety

Previously if I set in `spec/dummy/config/application.rb`: `config.threadsafe!` I would get the following failures:

    pages/spec/lib/refinery/pages/caching_spec.rb:5:in `<module:Pages>': uninitialized constant Refinery::Pages::Caching (NameError)
    pages/spec/lib/refinery/pages/url_spec.rb:5:in `<module:Pages>': uninitialized constant Refinery::Pages::Url (NameError)
    uninitialized constant Refinery::CLI

Requiring the libraries solves this issue.

I also fixed the naming convention for presenter specs.