fixes for trigger onenter/onleave

1- corrects onleavetrigger for deletions
2-adds a testObjects to trip onenter when creating or moving a trigger itself so that that will list objects already there as opposed to only going off when something moves into it

Engine/source/T3D/trigger.h

@@ -123,6 +123,7 @@ class Trigger : public GameBase
 
    static void consoleInit();
    static void initPersistFields();
+   void testObjects();
    bool onAdd();
    void onRemove();
    void onDeleteNotify(SimObject*);