* lang/python/examples/inter-edit.py: Update example.
* lang/python/gpgme.i (gpgme_edit_cb_t): Turn into
'gpgme_interact_cb_t'.
* lang/python/helpers.c (_pyme_edit_cb): Turn into
'_pyme_interact_cb_t'.
* lang/python/private.h (_pyme_edit_cb): Likewise.
* lang/python/pyme/constants/__init__.py: Replace numeric status codes
with the keywords.
* lang/python/pyme/constants/status.py: Likewise.
* lang/python/pyme/core.py (Context.interact): New method.
(Context.op_edit): Deprecate, update docstring, implement using
Context.interact.
* lang/python/tests/t-edit.py: Test both interfaces.