Add "Twin Sans" single stroke font

This font was derived from the Hershey fonts many years ago. Originally targeting embedded systems using the Twin window system, the tesselated curves were replaced with cubic splines both to make them look better and to save memory. At that point, coverage was increased to the whole ASCII set.

Since then, many of the glyphs have been redesigned to further simplify the outlines leaving a font that bears little resemblance to the original Hershey data. In addition, coverage has been extended to include the Latin-1 supplement as well as a selection of glyphs from the General Punctuation + Superscripts and Subscripts ranges.

I've placed it in the Hershey directory to respect its lineage.

Signed-off-by: Keith Packard keithp@keithp.com