'Add controller.
controller: Controller class'

def addController(self, name='c0', controller=None, **params):

    if (not controller):
        controller = self.controller
    if isinstance(name, Controller):
        controller_new = name
        name = controller_new.name
    else:
        controller_new = controller(name, **params)
    if controller_new:
        self.controllers.append(controller_new)
        self.nameToNode[name] = controller_new
    return controller_new
