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Created tests for heatmap chart
Added documention for heatmap chart
Modified heatmap example to use crossfilter group.
tests for composite chart when one crossfilter group is shared between 2+ sub charts

add sharing title options for composite chart

legend names bug fix. updated groupName chart storage index
Merge pull request #373
Merge pull request #357

Conflicts:
	test/legend-test.js
fix lint
Added BarChart legend tests, and reorganized legend tests
Moved legend tests for individual charts into chart tests
Merge pull request #374 from sclevine/barchart-legend

Added BarChart legend tests, and reorganized legend tests
Documented series chart
Added several tests for series chart, fixed subchart delegation bug.

_preprocessData needs to happen before _generateG in coordinateChart,
otherwise series chart options are not applied to subcharts
(for instance, transitionDuration, which needs to be 0 for tests).
Added series chart tests for seriesSort option
Add more direct unit tests for renderDataPoints and dotRadius.
Merge pull request #378
readded case in renderDataPoints for falsey arguments and added tests
Note that we cannot test transitions with jsdom
Merge pull request #380
pull request line dashStyle