10/24/2001

- use Perl subrange operator (0..10)
- convert gnuplot filehandles to using the FileHandle module
- do parameter checking on subroutines that are accessed by user
- set up multiple level of debugging
- find more robust way to handle temporary files. use MkTemp.pm.
- more support for xrt
- turn on display of the x2tics and y2tics
- Look into serious code integration and streamlining.  All use of
  ppmtogif should be handled by one routine in one module.  Right now
  Gnuplot and Xrt?d handle separately.
- If there is actually interest, allow for greyscale output from
  Gnuplot instead of our default of color.