IK work-in-progress commit;

- Removed old convention that only allowed one "IK" connection for Bones
  in a joint. Was highly frustrating for editing trees or branches.
  In a next commit, there will be a different method to define IK target
  and IK root, so this option actually will become "Connect Bone" or so.

- the IK group name is gone, now is just an option "Tree IK". When IK
  chains share a root they'll form a tree.
  Todo is preventing conflicts here (will be for editor to define IK Root)

- Adding new IK constraint with CTRL+I activates Constraint

source/blender/src/poseobject.c

@@ -299,6 +299,12 @@ void pose_add_IK(void)
 		set_constraint_target(con, ob, pchansel->name);
 	}
 	
+	/* active flag */
+	con->flag |= CONSTRAINT_ACTIVE;
+	for(con= con->prev; con; con= con->prev)
+		con->flag &= ~CONSTRAINT_ACTIVE;
+	
+	
 	ob->pose->flag |= POSE_RECALC;	// sort pose channels
 	DAG_scene_sort(G.scene);		// sort order of objects