removing mark background for pie chart and adding classes to slices and text in pie
removing mark background for pie chart and adding classes to slices and text in pie

ChakriCherukuri/bqplot,ssunkara1/bqplot,ChakriCherukuri/bqplot,ssunkara1/bqplot,rmenegaux/bqplot,dmadeka/bqplot,SylvainCorlay/bqplot,ChakriCherukuri/bqplot,dmadeka/bqplot,SylvainCorlay/bqplot,bloomberg/bqplot,bloomberg/bqplot,rmenegaux/bqplot,SylvainCorlay/bqplot,bloomberg/bqplot