title: ttk treeview: alternate row colors
body: <p>How can I set a style for <code>treeview</code> widgets so that alternate rows have different background colors, for example, rows 1,3,5 have white backgrounds and rows 2,4,6 have light blue-grey backgrounds?</p>
  
  <p>I'd also like to set <code>gridlines</code>.</p>