title: gmplot API issue
body: <p>i'm attempting to plot some items on a map using gmplot, my issue is that since the new google API changes it won't accept my API key? When I load the output I have the "for development purposes only" issue. Any help would be greatly appreciated.</p>
  
  <pre><code>import gmplot
  gmap = gmplot.GoogleMapPlotter
  
  gmap.apikey = "inserting my API key here"
  
  latitude_list = [ 30.3358376, 30.307977, 30.3216419 ]
  
  longitude_list = [ 77.8701919, 78.048457, 78.0413095 ]
  
  gmap = gmplot.GoogleMapPlotter(30.3184945,
                              78.03219179999999, 13)
  
  gmap.scatter( latitude_list, longitude_list, '# FF0000',
                              size = 40, marker = False)
  
  gmap.polygon(latitude_list, longitude_list,
                 color = 'cornflowerblue')
  
  gmap.draw("path to save .html")
  </code></pre>