Conversation view #839

Some email clients, allow to view message exchanges as conversations. Example would be gmail website or android app. Some email clients, for example aquamail for android, allow to switch between the two. Bitmessage should also allow this. However, it may require a new message type which contains references to previous messages, like Message-ID, References, In-Reply-To email headers.

Example of threading code by including explanation here: https://www.jwz.org/doc/threading.html

Requires #840