#TODO:
    
    * ask before unsubscribe, if a user click on the unsubscribe link. [derstappenit]

    * add validator to ENLSubsciber to check if this email already exists, 
      works now only for the portlet, but not if we use the add item menu. [derstappenit]

    * provide default values for sender_name, sender_address and test_email from portal_properties

    * cleanup of double opt-in tempobjects, don't use PasswordResetTool [derstappenit]
