statue patch (trunk only)

Pat wrote:
> <Someone> has a patch (we've added a couple of
> his earlier ones) which changes the statue display from a single
> one size fits all "`" to a gray monster symbol instead.
> But I think the idea is a good one, and along with the
> bouldersym option could make the fairly hard to
> distinguish back-tick character go away.

Sources tagged before applying NETHACK_PRE_STATUE,
and afterwards with NETHACK_POST_STATUE for easy
rollback.

include/hack.h

@@ -53,6 +53,7 @@
 #define MG_DETECT	0x04
 #define MG_PET		0x08
 #define MG_RIDDEN	0x10
+#define MG_STATUE	0x20
 
 /* sellobj_state() states */
 #define SELL_NORMAL	(0)