post: include eps files with "x X eps epsfile [width [height]]"

In neatroff \X'esp epsfile' includes the given EPS file with its lower
left corner at the current point.  For \X'epsfile w h' the EPS file is
scaled such that the width of its bounding box equals w and its height
equals h.  If h is missing, the height of the bounding box is scaled
as its width.
dev: mount fonts from given paths

If the second argument of the "x f" command contains a slash, neatroff
assumes that it is the path of the font description file.  Otherwise,
as before, the font is looked up in the output device directory.