Line2D: simplify set_data functionality; recache only a coord. that was set.
fix whitespace, one docstring in lines.py
pyplot.spy should set current image only if it is making an image
Fix cmap data for gist_earth_r, etc.
zorder support in figure: use same sort idiom as in axes
spines and ticks: implement smart bounds
spines: attempt to fix initial placement bug
spines: be clear about meaning of location vertices
spines: default transform is in data units, add set_bounds() call
spines: simplify code
