
1.  Add a 'flatten' argument to PostScriptTrace() so that can turn
    off path flattening and record curves as curves in RGML file
    (e.g., for systems that can draw curves, e.g., R in the future!).

2.  Bug in PostScriptTrace():  if PostScript image defines a path
    then does 'fill stroke' to fill the path then stroke it, the
    second path in the RGML file is empty (because PostScriptTrace()
    inserts a 'newpath').  A fix must NOT just remove the 'newpath'
    because otherwise separate paths just accumulate (e.g., the
    conversion of tiger.ps goes mental).

3.  Add tests/ code to check that PostScriptTrace() generates
    RGML code that is consistent with inst/dtd/rgml.dtd


