Reduce scuffing of random engravings

This changes the amount of scuffing that random engravings get when
they're first placed from 1-in-4 times the length of the text to 1-in-8.
This makes it possible for players to read the hints the game is trying
to give them.
Fix crash when item is unequipped/lost while being equipped (NetHack4)

This fixes a segfault that can occur if a quantum mechanic teleports you
onto a sink in the helplessness period of equipping levitation boots.

From NetHack4 commit 59c8439644ae3de012ec8148f0f1140424e7a0cd.
Show which hand levitation ring was on when forced off by a sink

e.g. "You crash to the floor!  You were wearing a ring of levitation (on
right hand)."  <-- Emphasis on the "(on right hand)" bit.
Make extended command prompt case insensitive (NetHack4)

Apparently this is the way NetHack does it too.

This uses strncasecmp() which is a POSIX function; if MinGW and/or
Cygwin complain about it not existing it shouldn't be too hard to write
ourselves.

From NetHack4 commit c6d4f7131e64aeb9a414c81fbdacefc48d1e4e58.
Guarantee one wish with wands of wishing (UnNetHack 5)

Wands of wishing come (1:1) to (1:3) instead of (1:0) to (1:2).

From UnNetHack commit 43a9ee2d50712590d821d65316e4fd6abf627beb.
Lower chances of rings exploding during charging (SporkHack)

Rings with enchantment +3 or lower will no longer have a chance to
explode when charged, and rings at -5 or lower will only explode from
cursed charging.
Changelog: Credit K-Mod for +1 to-hit for all short swords

This is meant to go with commit 305ccc6e0d (grant +1 to-hit for all
short swords, from K-Mod).