Fix AttributeError: module 'matplotlib.colors' has no attribute 'normalize'

[cgohlke]

Using matplotlib 2.0:

Running plotmap_masked.py
Traceback (most recent call last):
  File "D:\Build\basemap\basemap-git\examples\plotmap_masked.py", line 43, in <module>
    im = m.imshow(topodatm,palette,norm=colors.normalize(vmin=0.0,vmax=3000.0,clip=False))
AttributeError: module 'matplotlib.colors' has no attribute 'normalize'
TEST FAILURE (status=1)

See also http://matplotlib.org/api/colors_api.html#matplotlib.colors.Normalize

[WeatherGod]

how come we didn't notice this before?

[WeatherGod]

Found it... it was deprecated in v1.3 of matplotlib and finally removed.