python: Improve engine information handling.
* lang/python/gpgme.i (gpgme_engine_info_t): Wrap engine infos.
* lang/python/pyme/core.py (Context.engine_info): New property.
(Context.{g,s}et_engine_info): Improve docstrings.
* lang/python/pyme/results.py (EngineInfo): New class.- Signed-off-by: Justus Winter <justus@g10code.com>