Implement the IMPORT_FILES server command.
* src/server.c (cmd_file): Remove --continued stuff and add --clear. (conn_ctrl_s): Remove field files_finished. (impl_encrypt_sign_files): Adjust for this. (impl_decrypt_verify_files): Ditto. * src/server.c (impl_encrypt_sign_files): Add import feature. (cmd_import_files): Implement. * src/gpgmetools.h (gpa_import_result_s): New. * src/gpgmetools.c (gpa_gpgme_update_import_results): New. (gpa_gpgme_show_import_results): New. * src/gpaimportop.c (key_import_results_dialog_run): Remove. (gpa_import_operation_done_cb): Use new functions. * src/gpafileimportop.c, src/gpafileimportop.h: New.
The error and progress handling is not very pretty; this should be
improved similar to the verify command.