wght and wdth values

The OT spec allows for one range of wght and wdth values for those axes over the opsz range.

The developer can choose how the variation relates to those values and we have chosen to have smooth variation over the weights and widths from 100 to 900 at all sizes.

This makes the visible range of the 14 point default, a little more varied in width and wight at the same os/2 values than the 8 point, and a lot less varied at the same values in the 144 point.

The largest range, 144 point, are the wdth axes values currently assigned:
25%-100%-150%. I.E. the 144 pt width min is overall 1/4 the width of the 144 point regular (the 100%), and the width max is 150% of the width of regular.

This also means that the narrowest 14 and 8 point designs range from 25% to 150% even though their actual ranges are smaller.

Any changes to this should ideally be done before people start composing documents based on a font.