decaying globs of {ooze,pudding,slime}

Globs never rotted away but did become tainted after a relatively
short while, which seemed like a contradiction.  Change them to never
be tainted but shrink by 1 unit of weight approximately every 25
turns.  An ordinary glob (one that hasn't combined with any others)
starts out weighing 20 units, so it takes about 500 turns to vanish.
That's roughly twice as long as a corpse takes to rot away.

Shrinking globs give feedback when in hero's invent or in a container
in hero's inventory, but rarely (when going from an exact multiple
of 20 weight units; that is, from integral number of N globs to
N-1 + 19/20, or if weight reduction triggers an encumbrance change).
When a glob goes away completely, there is feedback for those two
circumstances and also for seeing the glob vanish from the floor.

I haven't touched how much nutrition eating a glob confers.  I have
changed formatting of glob names to use "small", "medium", "large",
"very large" instead of "small", [no adjective], "large", &c.  You
still need to have at least five globs coalesced together for the
adjective to become "medium", same amount as before.

I don't think EDITLEVEL needs to be modified but have incremented it
anyway to play things safe.

doc/fixes37.0

@@ -1228,6 +1228,10 @@ branch stairs have a different glyph, show up in yellow color in tty
 duration of confusion when drinking booze depends upon hunger state
 using 'D' allows dropping items picked up previously
 bones piles can be ransacked by adjacent monsters
+decaying globs of {ooze,pudding,slime} shrink over time based on their total
+	weight, eventually to nothing; for combined globs it can take a long
+	time, and while doing so they no longer give the tainted corpse food
+	poisoning effect when eaten
 
 
 Platform- and/or Interface-Specific New Features