resolve_references (PDF::Reader::Content)

    # File lib/pdf/reader/content.rb, line 451
        def resolve_references(obj)
          case obj
          when PDF::Reader::Stream then
            obj.hash = resolve_references(obj.hash)
            obj
          when PDF::Reader::Reference then
            resolve_references(@xref.object(obj))
          when Hash                   then obj.each { |key,val| obj[key] = resolve_references(val) }
          when Array                  then obj.collect { |item| resolve_references(item) }
          else
            obj
          end
        end