title: How to plot pandas DataFrame with date (Year/Month)?
body: <p>I've got a pandas dataframe populated with the following data : </p>
  
  <pre><code>      Date         val   count
  0  2013-01         A        1 
  1  2013-01         M        1
  2  2013-02         M        2
  3  2013-03         B        3
  4  2013-03         M        5
  5  2014-05         B        1
  </code></pre>
  
  <p>I'm new to matplotlib and couldn't figure how to plot this data using as Y axis (count), as X axis (Date) and having three separate curves, one for each value of val. </p>