title: How to use timestamp as chart's x-axis?
body: <p>I am trying to make a chart with Bokeh and I have a <code>datetime</code> list as below.</p>
  
  <p>I would like to set the <code>datetime</code> as my x-axis but seems like Bokeh can't show this chart correctly.</p>
  
  <p>Does anyone have a good solution?</p>
  
  <p>Thank you.</p>
  
  <pre><code>datetime = ['2017-11-23 20:56:16',
              '2017-11-23 20:56:47',
              '2017-11-23 21:00:56',
              '2017-11-23 21:01:26']
  
  p = figure(x_axis_type="datetime", plot_width=800, plot_height=350, title="the trend")
  
  p.xaxis.axis_label = "time"
  p.yaxis.axis_label = "price"
  p.line(datetime, price, line_width=2)
  
  output_file("test.html")
  show(p)
  </code></pre>