Pull request #585 fixes incorrect XOR logic caused by changes
accompanying introduction of gold dragons 5 or 6 weeks ago.
Closes #585
with spot where they think the hero is rather than where he really is
if hero died while wearing gold dragon scales/mail and left bones, they would
still be emitting light witout being worn when bones got loaded
+if an invisible monster put on or took off armor while out of hero's sight
+ spurious message "Suddenly you cannot see it" would be given
curses: 'msg_window' option wasn't functional for curses unless the binary
also included tty support