Detail:
- Reformatted the main source code so that it can be read by humans.

- Verified that it builds something which is functionally identical.

- Modified default max DA size to be a bit more useful for modern images.

- Changed sprite file output to name the sprite after the leafname of the source
  image (e.g. if source is "photo/jpg" the sprite in the sprite file is "photo").
  This is arguably much more useful than calling it after the processing options.
Admin:
  Untested but crunched BASIC compared by eye with previous revision.

Version 1.25. Tagged as 'ChangeFSI-1_25'