LOGOUTURL -- present a logout link

• Present a logout link, regardless of the state of login
• Syntax: %LOGOUTURL%
• Expand to: /bin/view/TWiki/VarLOGOUTURL?logout=1
• Category: LinkingAndNavigationVariables, UsersAndAuthenticationVariables
• Related: TWikiUserAuthentication, LOGIN, LOGINURL, LOGOUT, SESSIONID, SESSIONVAR, SESSION_VARIABLE