Add node argument to the toDict() callback

[mar10]

Inspired by this Stackoverflow question: http://stackoverflow.com/q/31440102/19166.
If we add a second argument to the callback, the usecase should work:

    var d = tree.toDict(true, function(dict, node){
        console.log('looking at ' + node.title);
        var tdList = $('>td', node.tr);
        /* read the attributes */
        dict.attr = { 
            ctime : tdList.eq(2).find("input").val(),
            filesize : tdList.eq(3).find("input").val(),
            user : tdList.eq(4).find("input").val(),
            group : tdList.eq(5).find("input").val(),
            permissions : tdList.eq(6).find("input").val()
        };
    });