Orange; Magical Group relink option. :)

This is the case:

- Empty has Group duplicator
- Empty has NLA strips to animate the group

On linking the Empty to another group (with button in ObjectButtons), it
checks for the current strips in NLA, and tries to find the proper objects
in the new Group, based on name matches.
If not found, it sets the strip-objects to zero.

source/blender/src/buttons_object.c

@@ -1340,6 +1340,10 @@ void do_object_panels(unsigned short event)
 		allqueue(REDRAWVIEW3D, 0);
 		DAG_object_flush_update(G.scene, ob, OB_RECALC_DATA);
 		break;
+	case B_GROUP_RELINK:
+		group_relink_nla_objects(OBACT);
+		allqueue(REDRAWVIEW3D, 0);
+		break;
 		
 	default:
 		if(event>=B_SELEFFECT && event<B_SELEFFECT+MAX_EFFECT) {
@@ -1510,7 +1514,7 @@ static void object_panel_anim(Object *ob)
 	uiDefButBitS(block, TOG, OB_DUPLINOSPEED, REDRAWVIEW3D, "No Speed",		234,130,82,20, &ob->transflag, 0, 0, 0, 0, "Set dupliframes to still, regardless of frame");
 	
 	uiDefButBitS(block, TOG, OB_DUPLIGROUP, REDRAWVIEW3D, "DupliGroup",		24,110,150,20, &ob->transflag, 0, 0, 0, 0, "Make copy of object for every frame");
-	uiDefIDPoinBut(block, test_grouppoin_but, ID_GR, REDRAWVIEW3D, "GR:",	174,110,142,20, &ob->dup_group, "Duplicate this entire Group"); 
+	uiDefIDPoinBut(block, test_grouppoin_but, ID_GR, B_GROUP_RELINK, "GR:",	174,110,142,20, &ob->dup_group, "Duplicate this entire Group"); 
 
 	uiBlockBeginAlign(block);
 	uiDefButS(block, NUM, REDRAWVIEW3D, "DupSta:",		24,85,141,19, &ob->dupsta, 1.0, (MAXFRAMEF - 1.0f), 0, 0, "Specify startframe for Dupliframes");