Things you might do to improve MailClient:
  MailComposeBean
	Do the sending in a new Thread, so you don't lock up the GUI.
	Extract the GUI code in MailComposeBean into its own class, and use
		it in MailReaderBean instead of all those calls to TextArea.append();
  MailReaderBean
	Move MailReaderBean loading code into a method, so we can load a new mbox.
		Catch FolderEvents and do it automatically!
	MailReaderBean needs a Reply button (implement addActionListener)
	MailReaderBean - handle HTML mail - use DataHandler.
	Catch AuthenticationFailedException, ask user for name and passwd again.
  General:
	Menus!!
	Options:
		Aliases in outgoing mail (Alias, AliasBean).
		Various reply options (Reply to sender, reply to all, etc.)
		Compose/Reply Templates?
	GUI to set things like protocol, hostname, etc. (done in JabaDex).
	More, and more consistent, error handling. Catch all exceptions!
	Exit: check if any unsent messages.
  S/Mime!
  Smile
