Enable default palette substitution
Detail: When output is switched to a sprite, but the sprite has no palette, substitute a default one. This mirrors a change made in RISC OS Select for ColourTrans 1.73. Admin: In support of Paint bounty work.
Detail: When output is switched to a sprite, but the sprite has no palette, substitute a default one. This mirrors a change made in RISC OS Select for ColourTrans 1.73. Admin: In support of Paint bounty work.