- added ``getthreadtitle()`` and ``setthreadtitle()``.
- Initialisation of the module moved to the first usage: importing the module
  doesn't cause side effects.
- Manage much longer command lines (#52)
- Improved build on BSD, dropped ancient versions (issue #67).
- Fixed build for Python 3.8 (#66, #72)
- Added support for Python 3.9
- Dropped support for Python < 3.6