'Create and return a menu (really button) bar.'

def createMenuBar(self):

    f = Frame(self)
    buttons = [('Hosts', (lambda : self.select('hosts'))), ('Switches', (lambda : self.select('switches'))), ('Controllers', (lambda : self.select('controllers'))), ('Graph', (lambda : self.select('graph'))), ('Ping', self.ping), ('Iperf', self.iperf), ('Interrupt', self.stop), ('Clear', self.clear), ('Quit', self.quit)]
    for (name, cmd) in buttons:
        b = Button(f, text=name, command=cmd, **self.menuStyle)
        b.pack(side='left')
    f.pack(padx=4, pady=4, fill='x')
    return f
