Added contacts->checkSuppression() and contacts->removeSuppression() for managing contact suppressions.
Added support for using either $email or $user_id in contacts->update().
Fixed an issue with underlying transactional API call attribute names.
Added a headers argument in events-send() and transactional->send(), enabling support for the Idempotency-Key header.
- Fixed client imports.
- Added test suite and some basic tests.
Initial release.