[securemail] Update Composer dependencies

- Update phpseclib/phpseclib to version 2.0.4
- Update singpolyma/openpgp-php to version 0.3.0

securemail/vendor/singpolyma/openpgp-php/examples/encryptDecrypt.php

@@ -0,0 +1,15 @@
+<?php
+
+require_once dirname(__FILE__).'/../lib/openpgp.php';
+require_once dirname(__FILE__).'/../lib/openpgp_crypt_rsa.php';
+require_once dirname(__FILE__).'/../lib/openpgp_crypt_symmetric.php';
+
+$key = OpenPGP_Message::parse(file_get_contents(dirname(__FILE__) . '/../tests/data/helloKey.gpg'));
+$data = new OpenPGP_LiteralDataPacket('This is text.', array('format' => 'u', 'filename' => 'stuff.txt'));
+$encrypted = OpenPGP_Crypt_Symmetric::encrypt($key, new OpenPGP_Message(array($data)));
+
+// Now decrypt it with the same key
+$decryptor = new OpenPGP_Crypt_RSA($key);
+$decrypted = $decryptor->decrypt($encrypted);
+
+var_dump($decrypted);