FLEX-34885 Added a new unit test class, ListCollectionView_PropertyChangeEvent_Tests, that not only tests a few scenarios to make sure that ListCollectionView reacts as expected to PropertyChangeEvents, but also makes explicit 2 of the consequences of manually dispatching PropertyChangeEvents through the VOs in the list without specifying a "property" and an "oldValue" in the PropertyChangeEvent: 1. null is assumed to have been replaced in the collection by that VO, so it will be removed if it already exists. This may be unexpected to developers. 2. if there's a customCompareFunction in the Sort object, it will be called with null as one of the arguments. This may again be unexpected to developers. NOTES: -also removed some whitespace and improved asdocs.