Date       Version
 5 Oct 93   1.0    initial release
 7 Oct 93   1.0.1  minor correction to best_mode_256 table
 8 Oct 93   1.1    hacked around an (undocumented?) problem concerning odd
                    logical_byte_widths and 16M modes
                   added missing JPEG header files to distribution
23 Oct 93   1.2    included jpeglib directory by default in Makefile
                   added 1280x1024 modes
                   added GIF/PPM/TARGA support using 16M/32K modes
24 Oct 93          added greyscale PPM colour map setting
                   corrected -F availability for GIF/PPM/TARGA
                   added colour map creation/lookup and changed GIF to use
                    256 modes and a colour map
