title: Bokeh time series plot
body: <p>I am trying to plot a time series value in Bokeh. I have a pandas dataframe as follows:</p>
  
  <pre><code>                    start_time                end_time  value
  0  2017-06-16 18:15:34.714 2017-06-16 18:34:59.335      0
  1  2017-06-16 18:34:59.335 2017-06-16 18:49:00.456      2
  2  2017-06-16 18:49:00.456 2017-06-16 18:52:59.638      0
  3  2017-06-16 18:52:59.638 2017-06-16 19:02:59.191      2
  4  2017-06-16 19:02:59.191 2017-06-16 19:09:00.078      2
  5  2017-06-16 19:09:00.078 2017-06-16 19:12:59.106      3
  6  2017-06-16 19:12:59.106 2017-06-16 19:17:59.567      2
  7  2017-06-16 19:17:59.567 2017-06-16 19:23:59.887      2
  8  2017-06-16 19:23:59.887 2017-06-16 19:32:00.095      2
  9  2017-06-16 19:32:00.095 2017-06-16 19:39:59.576      2
  10 2017-06-16 19:39:59.576 2017-06-16 19:44:59.836      2
  </code></pre>
  
  <p>I want to make a horizontal line plot that has y-axis corresponding to value. The line should have different color based on the value column. The horizontal line should be representative of start-time and end-time as well.</p>
  
  <p>I am playing around with bokeh plot but I am not able to do so. I tried resampling the time series as well. It would be very great if you could kindly help.</p>