This patch fixes/adds the following messages:

* ettin [zombies] and Vorpal Blade:
  "<Vorpal Blade> goes through both necks of <ettin> at once like butter!"
  "<Vorpal Blade> goes through both your necks at once like butter!"

* the Chromatic Dragon and Vorpal Blade:
  "<Borpal Vlade> cuts only a shallow wound in the thick skin of <Tiamat's> neck."
  [REAL CHANGE: NO BEHEADING IS DONE, JUST NORMAL DAMAGE]

* the following halluc mons are added:
 	catoblepas
	phoenix
	amphisbaena
		(medieval and ancient mythical creatures)
	pink oliphaunt
		(a Tolkienish gray mouse after C2H50H)
	black knight
		(Monty Python)
	Trogdor the Burninator
		(Homestar Runner, some silly/idiotic game that all freaks
		around me seem to love)

* when eating c*cktrice corpses while stoning-resistant:
  "Hmm... tastes like chicken."

* when eating a floating eye as a raven:
  "You peck the eyeball with delight."

* final disclose when hallucinated with >10 creature types vanquished
  ... "and a partridge in a pear tree"

* ascending when hallucinated:
  "The fat lady sings, and you are bathed in radiance..."

[Some of the ideas came from denizens of rgrn.]