A package for the DOM - Ajax
From a once-over:


You keep creating the same function in Pub.ajax:

    xhr.onload = function () {
        if (this.status === 200) {
            config_ajax.callback(xhr.responseText);
        }
    };


You could consider assigning this function once to a var onloadFunction which you then assign like this : xhr.onload = onloadFunction. On the whole, Pub.ajax needs to be reviewed by you with DRY in mind.
getBlockedProperty could be written in a much shorter fashion:

function getBlockedProperty(item) {
  return item ? item.blocked : false;
}

getIndexFromToken is odd, I have no idea what it really does, not a single variable or parameter is called token and there is not a single line of comment.
publik.addItem could use Object Literal Notation to make it more succint:

publik.addItem = function (callback) {
    var temp = {
      blocked : false;
      callback : callback;
      response_text : null;
    };
    queue.push(temp);
};

lowerCamelCasing -> You are not using it everywhere
A minor observation, would it not be much easier to just send synchronous requests instead of building a custom queue ?