Simplified the gruntfile, using file patterns
Adding grunt-karma to build system.
Moving boilerplate.js to a separate folder. Updating d3.v3.js to what was downloaded via bower.json. Grunt updates to include karma-coverage
Moved testing file to scatter.coffee. Made sure that a chart can be rendered.
Refactored test suite so that common code can be placed in test-utils.coffee
Tooltip tests for scatterChart.
Chart.update() tests for scatterChart.
Adding test files for bar charts, line, stacked, pie.
Removing 'description' property from pie model (wasn't being used).
Adding basic test coverage for bulletChart, cumulative line, historical bar, multibar horizontal, scatterplusline and sparkline.
README updates
Adding unit test coverage for axis.js
Adding more test coverage for axis.js (staggerLabels, rotateLabels)
Replaced getBBox with getBoundingClientRect
unit tests for core.js
unit tests for units.js
Merge pull request #671 from kashesandr/nvd3-testing

unit tests for core.js
Test coverage for Line Chart.
* test for interactive guideline.
axis.js unit test fixed
unit tests for legend.js partially
unit tests for the legend
unit tests for the pie chart