WillFilter breaks after calls to ActiveRecord::Relation#page in apps using will_paginate

[plerohellec]

Kaminari adds the page method to ActiveRecord::Relation. Kaminari actually makes this method name configurable but WillFilter uses the 'page' method name and doesn't support a configuration option to change it. As a result, in applications using will_paginate, WillFilter::Filter#results blows up:

    def results
      @results ||= begin
        ...

        if custom_conditions?
          recs = process_custom_conditions(recs.all)
          recs = Kaminari.paginate_array(recs)
        end  

        recs = recs.page(page).per(per_page)
        recs.wf_filter = self
        recs
      end
    end

on the call to "per" as the will_paginate page method will have been called instead of the Kaminari one.

WillFilter should make the method name configurable the same way Kaminari daes.