Override XMLHttpRequest.prototype.open for ajax calls

[barryvdh]

Based on the discussion here: symfony/symfony#8896

I'm not sure of support for different browsers etc, but there them seem to override XMLHttpRequest.prototype.open and add an eventlistener to read the header etc. That would mean it doesn't have to depend on jQuery (Angular? #139)

This could also mean that we show some extended information for ajax requests, perhaps a new tab for ajax requests, which also shows the time/status, and a link to load the dataset? And perhaps a toggle to refresh automatically etc.

So instead of bindToJquery, what about something like this:

bindToXHR: function() {
    var self = this;
    var proxied = XMLHttpRequest.prototype.open;
    XMLHttpRequest.prototype.open = function() {
        var xhr = this;
        this.addEventListener("readystatechange", function(method, url) {
            if (xhr.readyState == 4) {
                self.handle(xhr);
            }
        }, false);

        proxied.apply(this, Array.prototype.slice.call(arguments));
    }
}

(That misses the settings object from jquery, not sure how to get that).
Based on work from symfony/symfony#8896

[barryvdh]

So the code from symfony/symfony#12000 is now merged, so might be slightly different. Do you want me to make a PR for this?

[barryvdh]

Closed in favor of #167