* NEWS: Document new interfaces.
* doc/gpgme.texi: Document new interfaces.
* src/gpgme.h.in (GPGME_DELETE_ALLOW_SECRET, GPGME_DELETE_FORCE,
gpgme_op_delete_ext_start, gpgme_op_delete_ext): New.
* src/delete.c (delete_start): Change allow_secret argument to flags.
(gpgme_op_delete_ext, gpgme_op_delete_ext_start): New functions.
* src/engine-backend.h (delete): Change allow_secret argument to flags.
* src/engine.c (_gpgme_engine_op_delete): Likewise.
* src/engine.h (_gpgme_engine_op_delete): Likewise (for prototype).
* src/engine-gpgsm.c (gpgsm_delete): Likewise.
* src/engine-gpg.c (gpg_delete): Likewise.  Implement GPGME_DELETE_FORCE.
* src/gpgme.def (gpgme_op_delete_ext, gpgme_op_delete_ext_start): New.
* src/libgpgme.vers (gpgme_op_delete_ext, gpgme_op_delete_ext_start): New.