Update hatch documentation.
Oops in hatch_demo.py
Merge branch 'hatching'
Fix bug in earlier bugfix
Fix a bug in pdf usetex support
simplify calculation of geostationary limb
fix defn of llcrnrlon, urcrnrlon for pseudo-cyl projections
Document \mathdefault{} and \mathregular{} and the new mathtext.default rcParam.
Merge branch 'mathdefault'
fixed a mincnt problem with hexbin