nl_tokens: Subscribe for changes of a property or the whole object
pl_tokens: function ( property , <mask> ) { if ( typeof property != "string" ) { callback = property ; property = "__all__" ; } this . _subscribers [ property ] = this . _subscribers [ property ] || [ ] ; if ( this . _subscribers [ property ] . indexOf ( callback ) == - 1 ) { this . _subscribers [ property ] . push ( callback ) ; } }