Fix lint errors

This should fix every lint error, targeting Ruby 1.9.3. Tests are passing but given test coverage I'm not sure if that's much of a guarantee for it working properly, that said I think this should be fine.
This does one slight change: now Page.list is a valid method, which is the same as Page.all. I could disable this cop for this file, because rubocop doesn't like trivial accessors being manually created (it wants me to use attr_reader, which doesn't allow aliasing the name of `list` to `all` in its invocation.