fixup! Implement Reply-To header support when replying

Signed-off-by: Christoph Wurst <[email protected]>

tests/Unit/Model/IMAPMessageTest.php

@@ -147,6 +147,7 @@ public function testSerialize() {
 			'to' => [ [ 'label' => '[email protected]', 'email' => '[email protected]' ] ],
 			'cc' => [ [ 'label' => '[email protected]', 'email' => '[email protected]' ] ],
 			'bcc' => [ [ 'label' => '[email protected]', 'email' => '[email protected]' ] ],
+			'replyTo' => [ [ 'label' => '[email protected]', 'email' => '[email protected]' ] ],
 			'subject' => 'subject',
 			'dateInt' => 1451606400,
 			'flags' => [