cmdwin overhaul done

The afore-mentioned muck-wading is now over. It wasn't that bad, and I found a few more bugs that needed fixing up (for those of you playing the last release, try mixing 9999999999999999 mixtures of a spell and enjoy your extra reagents). I also decided to right-justify the cmdwin prompt when it gets too big to fit in the buffer, so you'll always see the latest verbage.