mimic statues & 2009 startup banner (trunk only)

A mimic posing as a statue was displayed as a tengu statue (and
recognizeable as such now that statues are displayed as the corresponding
monster rather than rock-class back tick), but the lookat code described
it as a giant ant statue (since there was no obj->corpsenm available to
indicate the monster type, it defaulted to 0).  This adds monst->mextra
field `mcorpsenm' so that mimics have a place to remember what sort of
statue or corpse they are mimicking.  And it picks a random monster type
when they take such forms so that the old tengu hack becomes irrelevant.

     newmextra() and newoextra() initialized pointers via memset(...,0)
which is not portable; switch to explicit assignments.  The wizard mode
code to display memory used for monsters and objects added in amounts
for the miscellaneous things pointed to by monst->mextra and obj->oextra
structs but didn't include memory for those structs themselves; add it.
Simplify monster save/restore slightly; there's no need for extra zeroes
to represent monst->mextra->X sizes when monst->mextra is null.

     Update the startup banner for 2009.  I should have done this with a
separate patch but I'm taking a shortcut.  :-]

include/patchlevel.h

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)patchlevel.h	3.5	2008/07/20	*/
+/*	SCCS Id: @(#)patchlevel.h	3.5	2009/01/30	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -13,10 +13,10 @@
  * Incrementing EDITLEVEL can be used to force invalidation of old bones
  * and save files.
  */
-#define EDITLEVEL	41
+#define EDITLEVEL	42
 
 #define COPYRIGHT_BANNER_A \
-"NetHack, Copyright 1985-2007"
+"NetHack, Copyright 1985-2009"
 
 #define COPYRIGHT_BANNER_B \
 "         By Stichting Mathematisch Centrum and M. Stephenson."