Recolor all book icons systematically

Color key:
Light red: martial arts
Light green: crafting recipes (primarily)
Magenta: teaches skill up to 1
Brown: teaches skill up to 2
Green: teaches skill up to 3-5
Cyan: teaches skill up to 6-7
Blue: teaches skill up to 8 or more
Pink: just (!) for fun, morale +1
Light blue: just for fun, morale +2
Light cyan: just for fun, morale +3
White: just for fun, morale +4 or more
Dark gray: book with special use case which doesn’t fit into any category above.
Light gray: Waste book. No skills, martial arts, crafting recipes, morale boost or special use case. Basically trash.
Yellow: intentionally unused
Dark red: intentionally unused
Merge remote-tracking branch 'Wuzzy2/book_icon_fix' into FrankenMod