histo.icn: Program to display simple histogram

This program displays a simple histogram based on numbers provided
in standard input.

The following options are supported:

     -s r    horizontal scale factors, default 1.0
     -w i    bar width in pixels, default 5
     -g i    gap between bars, default 1
     -m      minimal; set width to 1, gap to 0.
     n s     name for image file, default "untitled"

Note: If there is too much input, there may not be resources to
open a window, and even if there is, parts may be off-screen.

The histogram is written to <name>.gif

The window is dismissed by a user q event.