Fixed merge conflicts when merging with origin/nvd3-UI-134
Added back the 'tooltips' boolean flag to lineChart.dispatch.tooltipShow.
REbuilt nv.d3.js and minified version.
Instead of using a dispatch for handling 'highlightPoint' and 'clearHighlights', I am making
those functions a direct method of nv.models.scatter.  So you just say scatter.highlightPoint,
instead of scatter.dispatch.highlightPoint.
Exposed 'highlightPoint' and 'clearHighlights' in historicalBar.
The .nvd3 .nv-bars rect:hover style was incorrect. it needs to be "rect.hover",
because we are applying the hover class when we mouse over a bar.
Added historicalBar.interactive. If set to false, tooltips/hoverovers don't work.
Removed trailing commas in interactiveLayer code. Caused javascript error/warning.
Fixed bug in nv.interactiveBisect, for situations where the xAccessor is
function(d,i) { return i}