* src/cryptcontroller.cpp (CryptController::~CryptController):
Ensure overlay is stopped.
(vector_to_charArray): New helper.
(CryptController::lookup_fingerprints): User helper.
(CryptController::resolve_keys): Start crypto overlay.
(CryptController::stop_crypto_overlay),
(CryptController::start_crypto_overlay): New.
* src/cryptcontroller.h: Update accordingly.
* src/mail.cpp (Mail::reset_crypter): New.
(do_crypt): Reset crypter on error.
* src/mail.h: Update accordingly.