pick a slot

I'd say "good. things are progressing" if that progress hadn't been done while I can't get due sleep, coughing and sneezing. Anyway, I'm done with some basic steps to confirm that a multi-slot palette can be loaded in AnimEDS. Much remains, that will need more lunch-thinking.

• [done] ensure multi-slot palettes are read correctly.
• [done] buttons to pick slot on skeletton-setup page.
• [done] selected slots reflect in anim edition window.
• [done] move swap bits of AnimCommands to their hardware place, to make room for palette bits.
• [done] limbs table can reflect palette slots
• [done] palette slot preference stored in animations
• [todo] frame editor that obey colour preferences
• [done] preview using real colours
• [wish] timeline using real colours
• [done] size up to 8 palette slots for pendats to come in.
• [done] dumblador using multicols and bilou's feet.
• [done] Bilou using multicols for darker foot & hand. 
• [bugfix] saving something multipal with AnimEDS kills all the palettes
• [bug] sticky palettes selection when changing sprites?
• [SEDS, done] ensure palette reorganization works in multipalette .spr files.