- now also inherits status
- new method rebuild() builds a new tree from the elements already in the tree and those added with add(). As opposed to build() which deletes elements in the current tree and builds a new on from the added elements.
- size() now returns the number of elements in the actual tree (before either added or in tree).
- getNumberOfElements() deleted and instead getNumberOfAddedElements() added which returns the elements added with add() since construction or the last call to build() or rebuild().