add grunt, see more in README.md about how to use intstall and use grunt
FIxing bug in line.js.
Merge branch 'master' of https://github.com/novus/nvd3

Conflicts:
	nv.d3.min.js
Adding historical bar chart code.
ran make on nv.d3.js
Merge branch 'grunt' of https://github.com/lihongxun945/nvd3 into lihongxun945-grunt

Conflicts:
	nv.d3.min.js
fixed a merge conflict. No change to master code, so this commit is not tagged
Merge branch 'master' of https://github.com/novus/nvd3

Conflicts:
	examples/historicalBarChart.html
	nv.d3.js
	nv.d3.min.js
	src/models/historicalBarChart.js
	src/nv.d3.css
Adding PNG image to show what a sample line chart looks like. For the WIKI documentation.
Fixed two stacked area chart issues:
1. When in expanded view in stacked area chart, if there is missing data (zero data), 'holes' will be displayed in the chart where data is missing.
2. Tooltips used to be disabled if the stacked area showed values less than zero. This functionality has been disabled.
Added 'rightAlign' property to legend.js (defaults to true). If set to 'false', legends become left aligned.
updated multiChart to allow changing yDomain on yscales
Merge branch 'master' into development

Conflicts:
	nv.d3.js
Merge branch 'development' of https://github.com/novus/nvd3 into development

Conflicts:
	nv.d3.min.js
Merge branch 'development' of https://github.com/novus/nvd3 into development

Conflicts:
	nv.d3.min.js
Created nv.models.tooltip in tooltip.js.
This new model encapsulates most of the tooltip functionality.
Updated nv.models.tooltip to have a custom HTML content generator. The default is to put tooltip inside a <table> tag.
Updated scatter.js so that when you mouseover a path-point, it will return all series information in the mouse event dispatch.
Updated nv.models.tooltip with more features.
Updated styling of the tooltip.
Added the 'highlightPoint' dispatch on nv.models.scatter. This dispatch lets the programmer highlight any point on any series.
Currently used in lineChart to highlight points.
Added color legend square to the tooltip for each series.