print error message if can't open boundary datasets
Now only install 'i' and 'h' datasets.
install 'c' and 'l' boundary datasets by default.
fixed a barh bug
more updates for 0.9
Fixes to drawmapboundary method.
fix minor bug when printing version number of required matplotlib
if resolution=None, no boundary data is needed (requested by Andrew Straw).
Updates for new set_aspect syntax
applied wx backend deprecation warning patch
