gpg: New list-options show-pref and show-pref-verbose.
* g10/options.h (LIST_SHOW_PREF): New. (LIST_SHOW_PREF_VERBOSE): New. * g10/gpg.c (parse_list_options): Add new options. * g10/keyedit.c (show_prefs): Factor code out to ... * g10/keylist.c (show_preferences): new. (list_keyblock_print): Call show_preferences.