Set default table column widths based on content.

[kannes]

data_table = toyplot.data.read_csv("/usr/share/gdal/stateplane.csv")
data_table = data_table[:10]
canvas = toyplot.Canvas()
table = canvas.table(data_table)

gives me

You can see that there is no visible margin between the STATE and ZONE columns (at the bottom "CALIFORNIAIII" instead of "CALIFORNIAIII" and the headers of PROJ_METHOD DATUM as well as USGS_CODE and EPSG_PCS_CODE overlap.

I know I can manually edit the column widths, but it would be nice if the default was not overlapping, focusing on safe readability.