+ a default font with IBM extended ASCII codes more suitable for ANSI art.
+ color-map settable from command line
+ automatic sizing of output gif based on ansi

Far-Out-There
+ Scrolling animated gif.  I.e. simulate the console when y>y_size

+ Input from stdin, output to stdout?
+ Set output automatically based on filename
+ create safe temp files in /tmp
+ Fuzz testing
