* remove duplicate unit test
* unit test (currently failing) for issue 4267
* bugfix: ensure doc.ents preserves kb_id annotations
* fix in setting doc.ents with empty label
* rename
* test for presetting an entity to a certain type
* allow overwriting Outside + blocking presets
* fix actions when previous label needs to be kept
* fix default ent_iob in set entities
* cleaner solution with U- action
* remove debugging print statements
* unit tests with explicit transitions and is_valid testing
* remove U- from move_names explicitly
* remove unit tests with pre-trained models that don't work
* remove (working) unit tests with pre-trained models
* clean up unit tests
* move unit tests
* small fixes
* remove two TODO's from doc.ents comments
