function ModeBar(opts) {
    this.container = opts.container;
    this.element = document.createElement('div');

    this.update(opts.graphInfo, opts.buttons);

    this.container.appendChild(this.element);
}
UI controller for interactive plots
@Class
@Param {object} opts
@Param {object} opts.buttons    nested arrays of grouped buttons config objects
@Param {object} opts.container  container div to append modeBar
@Param {object} opts.graphInfo  primary plot object containing data and layout