title: fix colorbar range in basemap python
body: <p>I'm plotting a 2D temperature array over a world map, using <code>Basemap</code>. All works fine, except for the colorbar, that I want to fix within a certain range Tmin-Tmax. Unfortunately, <code>vmin</code> and <code>vmax</code> that I use for matplotlib, here seem not to work and I wasn't able to find the right keywords (if any) used for this purpose. Any suggestion? Thanks.</p>
  
  <pre><code>fig = plt.figure(figsize=(20,10))
  map = Basemap(projection='cyl', lat_0 = 57, lon_0 = -135, resolution = RES, area_thresh = 0.1, llcrnrlon=-180., llcrnrlat=-90., urcrnrlon=180., urcrnrlat=90.)
  map.drawcoastlines()
  map.drawcountries()
  map.drawparallels(np.arange(-90,90,15),labels=[1,1,0,1])
  map.drawmeridians(np.arange(-180,180,15),labels=[1,1,0,1])
  map.drawmapboundary()
  map.imshow(IR1)
  cbar = map.colorbar(location='right', pad="5%")
  cbar.set_label('T [Celsius]')
  plt.title("temperature")
  plt.savefig("temperature.png")
  </code></pre>