Add stacked chart for transit length indicator

Filters indicator endpoint to only return system/mode indicators

Refactors some of the stuff in data-controller to data-service
and attempts to clean up the chart definition objects.

See notes in data-partial.html regarding use of ng-init
to temporarily store data transformations.
Do you mean the function in a function?

If so, no. It's what the nvd3directive expects, and I figured it was more explicit than having some sort of helper method that wraps them for us. And, a helper method of some kind would still be another function call anyways.