Ordinal number support

[TrySound]

I like this project a lot but I forced to use Numeral-js which has ordinal numbers support like 1st, 2nd etc.

Is there plan to support it? I can send a PR so we could discuss implementation.

[mbostock]

Related d3/d3-time-format#10.

[mbostock]

I’d be happy to discuss implementation. One challenge I foresee is whether or not the ordinal suffixes would be localizable, and whether the English implementation generalizes to other locales.