Paginate default page

depends on cleaned up version of previous pr #1187, w/paginator.validate_number. 

adds a setting with existing default value of 1 to allow specifying a default page via setting or class-static.

this avoids adding a new paginator and addresses the need of an alternate default value where it's created. Django's built-in pagination doesn't require this sort of setting since you manually create the pagination objects rather than having them created on the fly from settings/attributes as is the case here.

questions/comments/suggestions welcome