Add a max-width argument for marks with type=bar

[jwildfire]

With sparse data, we regularly get charts where a single bar takes up an entire plot (See below). Can be overcome with range_band, but then you run the risk of the bars not scaling well when there are lots of observations later on. Should be doable by putting a quick logic check on range_band on resize.

[jwildfire]

On second thought, I think range-band is sufficient here. Closing.

[samussiah]

That's a lot of extraneous data ink.