added 'lower_head', 'upper_head' to bokeh ErrorBars plot
@@ -418,7 +418,7 @@ class SideHistogramPlot(ColorbarPlot, HistogramPlot):
class ErrorPlot(ElementPlot):
- style_opts = line_properties
+ style_opts = line_properties + ['lower_head', 'upper_head']
_mapping = dict(base="base", upper="upper", lower="lower")
