title: How to use Bokeh datetimetickformatter to customize ticks
body: <p>I am relatively new to python and I am using bokeh to create a html file that plots some timeseries data.</p>
  
  <p>I would like to format the x-axis ticks as "DD/MM HH:SS". I am writing a simplified version of the code:</p>
  
  <pre><code>from bokeh.plotting import figure, output_file, save, show
  from bokeh.models import DatetimeTickFormatter
  import datetime as dt
  t=[dt.datetime(2017, 1, 9, 16, 14, 10),dt.datetime(2017, 1, 9, 16, 15, 20)]
  Temp=[200,210]
  output_file("Burner SPC test.html")
  p1=figure(title="Tip1 TC", x_axis_label="Time", y_axis_label="Temp Diff", x_axis_type="datetime")
  p1.line(t,Temp)
  p1.xaxis.formatter=DatetimeTickFormatter(formats=dict(
  days=["%??"],
  months=["%??"],
  hours=["%???"],
  minutes=["%???"])) #not sure how to format here to get the desired output
  show(p1)
  </code></pre>
  
  <p>Any help is highly appreciated.
  Thanks in advance.</p>