Magic portals and levitation boots

From a bug report.  Removing levitation boots while hovering over
a magic portal causes the portal to be delayed since it takes time to
remove the boots.  This causes the portal to be taken via unmul in allmain.
At that point, the will activation message display but you won't teleport
until you type something.  Handle the delayed goto after unmul completes.

doc/fixes34.1

@@ -180,6 +180,8 @@ effect of wearing or removing the Eyes of the Overworld took effect on the
 dragon scale mail is magic armor
 invoking or applying an artifact must pass a touch_artifact check
 document 'D'rop BUCX behavior in the Guidebook
+remove levitation boots over a portal, the portal teleport is delayed until
+	 your next command is typed.
 
 
 Platform- and/or Interface-Specific Fixes

src/allmain.c

@@ -283,10 +283,13 @@ moveloop()
 
 		    /* when immobile, count is in turns */
 		    if(multi < 0) {
-			if (++multi == 0)	/* finished yet? */
+			if (++multi == 0) {	/* finished yet? */
 			    unmul((char *)0);
+			    /* if unmul caused a level change, take it now */
+			    if (u.utotype) deferred_goto();
+			}
 		    }
-		}			
+		}
 	    } while (youmonst.movement<NORMAL_SPEED); /* hero can't move loop */
 
 	    /******************************************/