title: Bokeh: xwheel_pan and ywheel _pan tools not working
body: <p>I'm a bit new to Bokeh, and I've been struggling with getting the xwheel_pan tool to work. I've tried this. I can change the tools argument to <a href="https://docs.bokeh.org/en/latest/docs/reference/models/tools.html?highlight=pan#bokeh.models.tools.Scroll" rel="nofollow noreferrer">anything</a> except xwheel_pan and ywheel_pan for some reason. I'm using Bokeh version 1.4.0</p>
  
  <pre><code>import numpy as np
  from bokeh.plotting import figure, show
  
  p = figure(plot_width = 900, tools='xwheel_pan')
  lines = [p.line(np.arange(10), np.random.random(10)) for i in range(3)]
  
  show(p)
  </code></pre>