Terminal driver dxf for export to AutoCad (Release 10.x).
It has no options. The default size is 120x80 AutoCad units.
dxf uses seven colors (white, red, yellow, green, cyan, blue and magenta)
that can be changed only by modifying the source file. If a black-and-white
plotting device is used the colors are mapped to differing line thicknesses.
Note: someone please update this terminal to the 2012 DXF standard!
