python: Improve and test Context.wait.
* lang/python/pyme/core.py (Context.wait): Improve docstring. As the context passed to 'gpgme_wait' is never NULL, it is pointless to look at the returned context. Always raise exceptions. * lang/python/tests/Makefile.am (pytests): Add new test. * lang/python/tests/t-wait.py: New file.
- Signed-off-by: Justus Winter <justus@gnupg.org>