Bug Fixes
* add base props ()
* bad merge ()
* clean up 6dof after merge ()
* clean up base properties ()
* dtype default ()
* exception text ()
* fix BaseModel derivations ()
* linting ()
* linting ()
* mypy ()
* mypy ()
* remove MultiBox ()
* rename file ()
* spelling ()
* style ()
* update doc strings ()
* validate control against gym space ()
Features
* add tests ()
* define spaces as props held by parts ()