test symbolSize, excludedSize, emptyOpacity
test symbolSize, excludedSize, emptyOpacity

s/hidden/empty/g
for #1058 and cleanup

dc-js/dc.js,mtraynham/dc.js,TheDataShed/dc.js,mtraynham/dc.js,mtraynham/dc.js,mtraynham/dc.js,dc-js/dc.js,aaronhoffman/dc.js,TheDataShed/dc.js,dc-js/dc.js,mtraynham/dc.js,TheDataShed/dc.js,dc-js/dc.js,aaronhoffman/dc.js,aaronhoffman/dc.js,aaronhoffman/dc.js,TheDataShed/dc.js,aaronhoffman/dc.js,dc-js/dc.js,TheDataShed/dc.js