implement _hit_span for all markers
implement _hit_span for all markers

philippjfr/bokeh,schoolie/bokeh,philippjfr/bokeh,ericmjl/bokeh,schoolie/bokeh,stonebig/bokeh,mindriot101/bokeh,timsnyder/bokeh,stonebig/bokeh,rs2/bokeh,timsnyder/bokeh,ericmjl/bokeh,DuCorey/bokeh,mindriot101/bokeh,rs2/bokeh,timsnyder/bokeh,ericmjl/bokeh,jakirkham/bokeh,bokeh/bokeh,DuCorey/bokeh,aavanian/bokeh,aavanian/bokeh,schoolie/bokeh,rs2/bokeh,percyfal/bokeh,bokeh/bokeh,schoolie/bokeh,bokeh/bokeh,Karel-van-de-Plassche/bokeh,philippjfr/bokeh,schoolie/bokeh,percyfal/bokeh,percyfal/bokeh,timsnyder/bokeh,Karel-van-de-Plassche/bokeh,bokeh/bokeh,ericmjl/bokeh,jakirkham/bokeh,philippjfr/bokeh,Karel-van-de-Plassche/bokeh,jakirkham/bokeh,DuCorey/bokeh,timsnyder/bokeh,DuCorey/bokeh,aavanian/bokeh,ericmjl/bokeh,dennisobrien/bokeh,dennisobrien/bokeh,mindriot101/bokeh,dennisobrien/bokeh,rs2/bokeh,dennisobrien/bokeh,stonebig/bokeh,rs2/bokeh,bokeh/bokeh,Karel-van-de-Plassche/bokeh,aavanian/bokeh,philippjfr/bokeh,stonebig/bokeh,mindriot101/bokeh,dennisobrien/bokeh,DuCorey/bokeh,aavanian/bokeh,percyfal/bokeh,jakirkham/bokeh,percyfal/bokeh,Karel-van-de-Plassche/bokeh,jakirkham/bokeh