update Namespace Reference

Detailed Description

-images

Find image files with magic expansion and convert them for use with stratagus.
*-rgb.png: convert from RGB to stratagus palette
*-big.png: shrink to half size, then convert from RGB as above
TODO *.xcf: assumed to be the source of the same .png, print warning if newer

Planned: What about something like this? Would this help?
*-playercolor.png, *-unit.png: first is converted to gray, then puzzled together
                           with the right palette entries