sleeping steeds (trunk only)

From the newsgroup:  it was possible to saddle, mount, and ride on a
sleeping jabberwork without it ever waking up.  Movement was checking for
timed sleep (!mon->mcanmove, set when mon->mfrozen contains a timer count
for either sleep or paralysis) but not indefinite sleep (mon->msleeping).
This moves the checking into its own routine which handles both types.
And it gives monsters a chance to wake up when they get saddled or mounted.

src/mhitm.c

@@ -1277,7 +1277,7 @@ int amt, how;
 		(how >= 0 && resist(mon, (char)how, 0, NOTELL))) {
 	    shieldeff(mon->mx, mon->my);
 	} else if (mon->mcanmove) {
-	    mon->meating = 0;	/* terminate any meal-in-progress */
+	    finish_meating(mon);	/* terminate any meal-in-progress */
 	    amt += (int) mon->mfrozen;
 	    if (amt > 0) {	/* sleep for N turns */
 		mon->mcanmove = 0;