'Add the spin box for maximal number of attributes'

def __init__(self, master):

    VizRankDialog.__init__(self, master)
    OWComponent.__init__(self, master)
    box = gui.hBox(self)
    self.max_attr_spin = gui.spin(box, self, 'max_attrs', 2, 4, label='Limit    the    number    of    attributes    to:    ', controlWidth=50, alignment=Qt.AlignRight, callback=self.max_attr_changed)
    gui.rubber(box)
    self.layout().addWidget(self.button)
    self.attr_ordering = None
    self.marginal = {}
    self.last_run_max_attr = None
