Add options --gpg-binary and --gpgsm-binary.
* src/gpgmetools.c (gpa_switch_to_gpg2): Add args GPG_BINARY and GPGSM_BINARY. * src/gpa.c (struct gpa_args_t): Add fields gpg_binary and gpgsm_binary. (option_entries): Add options --gpg-binary and --gpgsm-binaries. (main): Pass option values to gpa_switch_to_gpg2.