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
Merge remote-tracking branch 'upstream/master'

Conflicts:
	dc.min.js
legend click action and colors for composite chart