Commit 00607ec260efa4cfe10f9b36d6e3d3590ae92d79

DRC 2020-01-08T14:22:35

Eliminate unnecessary NULL checks before tjFree() + document that tjFree() accepts NULL pointers without complaint. Effectively, it has had that behavior all along, but the API does not guarantee that tjFree() will be implemented with free() behind the scenes, so it's best to formalize the behavior.