simplify tree class

implement cxTreeDestroyNode and cxTreeDestroySubtree - resolves #438

fix missing free() in test_array_insert_sorted

fix missing free() in test_tree_add_duplicate_root

fix uninitialized simple_destructor - fixes #443

implement cxTreeRemove() with re-link function

rename cxTreeRemove() to cxTreeRemoveSubtree()

fix bug when removing the root node of a tree

add test for simple destructor in trees - fixes #436

complete implementation of remaining high level tree functions

(0) -300 -100 -10 +10 tip

mercurial