Composite chart legend names bugfix

Hi, Nick!
You're doing a great job making such a cool library!
I found a little bug in composite chart legend behaviour.
When one crossfilter group is shared between 2+ sub charts with custom valueAccessor, title of only one series will be displayed on the legend and undefined values in the sub charts tooltip.

Code with problem before fix: http://jsfiddle.net/68BUX/1/
Code after fix: http://jsfiddle.net/7j2vc/2/