title: add labels to points bokeh
body: <p>I have the following based on their docs:</p>
  
  <pre><code>album_names = ['Ctrl', 'Ctrl', 'Z', 'Ctrl', 'Ctrl', 'Z', 'Ctrl', 'Ctrl', 'Ctrl', 'Ctrl', 'Z', 'Z', 'Z', 'Z', 'Z', 'Z', 'Z', 'Ctrl', 'Ctrl', 'Ctrl', 'Ctrl', 'Ctrl', 'Ctrl', 'Z']
  valence = [0.37, 0.598, 0.481, 0.166, 0.413, 0.0798, 0.549, 0.332, 0.348, 0.335, 0.355, 0.22, 0.433, 0.158, 0.357, 0.134, 0.367, 0.237, 0.248, 0.239, 0.535, 0.432, 0.505, 0.142]
  energy = [0.579, 0.686, 0.551, 0.367, 0.61, 0.475, 0.488, 0.525, 0.534, 0.517, 0.56, 0.342, 0.688, 0.505, 0.551, 0.63, 0.71, 0.453, 0.518, 0.708, 0.463, 0.684, 0.296, 0.576]`
  
  df = pd.DataFrame([album_names, energy, valence]).T
  df.columns = ['album_name', 'energy', 'valence']
  </code></pre>
  
  <p>I want to make a scatter plot using bokeh with valence on the x axis, energy on the y axis. Also, when you hover over each point, I want it to say it's value for <code>album_name</code>. And the color of the point is based <code>album_name</code>.</p>
  
  <p>I have tried the following:</p>
  
  <pre><code>from bokeh.models import ColumnDataSource, Range1d, LabelSet, Label
  from bokeh.io import output_notebook, show
  from bokeh.plotting import figure
  from bokeh.palettes import brewer
  
  source = ColumnDataSource(data=dict(valence=valence,
                                      energy=energy,
                                      names=album_names))
  
  p = figure()
  p.scatter(x='valence', y='energy', size=8, source=source)
  labels = LabelSet(x='valence', y='energy', text='names',
                    level='glyph', x_offset=5, y_offset=5,
                    source=source, render_mode='canvas')
  
  p.add_layout(labels)
  show(p)
  </code></pre>
  
  <p>But this does not show the album name as you hover over the point. It fixes the album name next to the point. Any help in getting the album_name to show only when hovering over the point and changing the color based on the value of album_name would be greatly appreciated</p>
  
  <p>Note: it would like similar to below
  <a href="https://i.stack.imgur.com/nQ65l.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/nQ65l.png" alt="enter image description here"></a></p>