Bring into line with master commit b055b2a5.

This revision includes the fixes for "JUMP STREAM" and "THROW AXE"
in Adventure 6, and the missing synonym "POTTERY" and spurious
synonym "SLAY" in Adventure.

I've removed the scavenger-hunt tweaks from Adventure 3. It now
exactly matches what you get by "cd ODWY0550; make" in the current
master branch.