ID for vertexes can't handle two vertexes with same key, shows them as one instead of two different vertexes. #19
Description
For BBT, if two vertexes has the same key but are two different vertexes they are shown as one vertex instead of 2 in image.
A students tree looked correct, however is_bst() returned false. After a remove the student forgot to update parent referens to new node. But the old and the new parent both had the same key so treevizer showed a correct tree instead of showing two vertexes with the same key.