The bin transform should coerce inputs to numbers

[mbostock]

This currently does not do what I expect:

Plot.rectY(["9.6", "9.6", "14.8", "14.8", "7.2"], Plot.binX()).plot()

I expect the data to be explicitly coerced to numbers since Plot.binX implies that x is quantitative.

Plot.rectY([9.6, 9.6, 14.8, 14.8, 7.2], Plot.binX()).plot()