Add scale metadata for Map and Pie.
Add scale metadata for Map and Pie.

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