Add keycache for located keys
* src/keycache.cpp, src/keycache.h: New. * src/Makefile.am: Add new files. * src/mail.cpp (in_de_vs_mode): Move to cpphelp. Rename global maps to s_ prefix to be more clear. (Mail::locate_keys): Use keycache. (do_locate): Removed. (Mail::locate_all_crypto_recipents): New. * src/cpphelp.cpp: Add in_de_vs_mode. * src/ribbon-callbacks.cpp (mark_mime_action): Trigger locate on crypto toggle.
Every serious MUA needs a Keycache ;-)
This is needed to store the keys returned by
gpg --locate-keys if we want to use them later to automatically
send to the keys located this way.