Major change to interactiveLayer.js. Instead of creating
a svg <rect> element to process mousemove events, we are
attaching the mousemove event to the bounding <svg> container.
This allows stackedAreaChart to maintain some previous interactivity.
Merge branch 'development' of https://github.com/novus/nvd3 into development
Overhauling the logic for creating an interactive layer.
Basically, the <svg> container will now process all mousemove
events. This allows stackedAreaChart and CumulativeLineChart to
maintain some other forms of interaction.
Rebuilding nv.d3.js