* The fillcontinents method doesn't always do the right thing.  Matplotlib
always tries to fill the inside of a polygon.  Under certain situations,
what is the inside of a coastline polygon can be ambiguous, and the 
outside may be filled instead of the inside. 
Workarounds - change the map projection region slightly or
mask the land areas with the drawlsmask method instead of
filling the coastline polygons (this is illustrated in the ortho_demo.py example). 
