title: How to create a multi-line plot title in bokeh?
body: <p>How do you create a multiline plot title in bokeh?... same question as <a href="https://github.com/bokeh/bokeh/issues/994" rel="noreferrer">https://github.com/bokeh/bokeh/issues/994</a><br>
  Is this resolved yet?</p>
  
  <pre><code>import bokeh.plotting as plt
  
  plt.output_file("test.html")
  plt.text(x=[1,2,3], y = [0,0,0], text=['hello\nworld!', 'hello\nworld!', 'hello\nworld!'], angle = 0)
  plt.show()
  </code></pre>
  
  <p>Additionally, can the title text string accept rich text?</p>