Encapsulate the method's of rulings from class Page

[ShienF]

Encapsulate rulings method from class Page into class Rulings. Make methods about rullings more object-oriented.

[jeremybmerrill]

I like this. What do you think @jazzido ?

I'd like to do a little bit of clean-up (e.g. erasing the TODO comment on L26 that's solved by this PR.) but otherwise very into it.

Noting that I haven't actually run the tests with this patch; don't have a dev env set up on this particular laptop.

[jeremybmerrill]

and @ShienF thanks very much for the PR and sorry for the wait