Polisher is a module, not a class.

Fixes the error 'Polisher is not a module (TypeError)' when the version.rb is loaded via the gemspec before the various class files.
As an example, this occurs when you run bundle exec rake spec.
Merge pull request #9 from jrafanie/fix_polisher_is_not_a_module_error

Polisher is a module, not a class.