fixed bug in PrintoutWX--thanks to Ziwen Fu
Import quad2cubic from mlab, not the nonexistent numerical_methods
Fix double rendering when saving PNGs with Agg backend.
minor typo
Separate drawstyles and linestyles for lines
more workarounds for geos library version 3
fixed numerical methods imports -> mlab
moved nemerical methods back to mlab pending more comprehensive reorg
fix bug in "angles='xy'" support in quiver
Change quiver angles kwarg from radians to degrees
