title: mplleaflet: Add the plot legend and select initial zoom
body: <p>Can anyone guide me on how to add a legend to the mplleaflet html plot. And second how to choose an initial zoom?</p>
  
  <p><em>open shapefile in geopandas and plot property on interactive web map</em></p>
  
  <p>Example Code: </p>
  
  <pre><code>import geopandas as gp
  shapefile = 'shapefile/ne_50m_admin_0_countries.shp'
  df_shapefile_countries = gpd.GeoDataFrame.from_file(shapefile)
  
  import mplleaflet
  ax = df_shapefile_countries .plot(column='pop_est')
  mplleaflet.show(fig=ax.figure)
  </code></pre>
  
  <p>Example Image: 
  I would like to immediately zoom for example to South East Asia</p>
  
  <p><a href="https://i.stack.imgur.com/MjX6H.png" rel="noreferrer"><img src="https://i.stack.imgur.com/MjX6H.png" alt="World map "></a></p>