Add support for stepwise Area plots
Add support for the `step` option of the matplotlib `fill_between` method.
@@ -209,7 +209,7 @@ class AreaPlot(AreaMixin, ChartPlot):
style_opts = ['color', 'facecolor', 'alpha', 'edgecolor', 'linewidth',
'hatch', 'linestyle', 'joinstyle',
- 'fill', 'capstyle', 'interpolate']
+ 'fill', 'capstyle', 'interpolate', 'step']
_nonvectorized_styles = style_opts
