access original data rows from aggregated series data

[jabadia]

In order to extend dimple for some useful use cases, I would like to have an array of the original data rows accessible from the series data rows:

1. That would allow to create more meaningful tooltips using row fields that are not used in any axis
2. I want to do a 'candlestick' chart. I could write a plot.candle function and access min, avg, and max fields for each data point to draw the candle accordingly.