Plus2: Update unrand weapons (todo demon axe and 27)

Leech receives a buff to +8 and increased penalties (-2 instead of -1).
Plus2: Sprints
Plus2: Trog/Oka and some other stuff
Plus2: (JEWEL/WPN) Simplify
Plus2: Upgrade old weapons

Their new (single) enchantment is the old to-dam if negative, else the max of
its to-hit and to-dam enchantments. Blowguns already only used to-hit while
setting to-dam to 0, so their levels are unchanged.

In the interest of a simple and consistent upgrade path, this was chosen over
weighted averages of the enchantments and whatnot. For very specific cases,
the change will buff existing items quite a bit, and for a few unrandarts it
will also upgrade them to numbers that are not "correct" after modifying the
unrand definitions.
Plus2: Remove from ng-setup (and readability) (REVIEW)
Plus2: l_item and attempt at trove fixup
Combine all three enchant weapon scrolls

New item is just called "scroll of enchant weapon".  It increases both accuracy
and damage by 1.

Enchant weapon III scrolls have been converted to stacks of 2 enchant weapon
scrolls where placed in vaults, and if already generated will act like a common
"scroll of enchant weapon" as well for sake of simplicity.

Scroll weights have been adjusted a bit. Both EW1 and EW2 were weighted at 331
before, and EW3 additionally at 140. One of those 331 is gone now, resulting in
a typical game having slightly more scrolls that are not enchant weapon.