document dc.transition
document dc.transition

fix dc.disableTransitions doc
remove callback from dc.optionalTransition

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