Added the current form to the context of the remote ajax request

Hi,

I've added the current form as the context for the ajax request for a remote validation call. Now we are able to do:
```javascript
$form.bind("ajaxSend", function (e, xhr, settings) {
                    
}).bind("ajaxComplete", function (e, xhr, settings) {
                   
});
```
This allows us for example to show a loading animation on a specific input control when the remote call is being made (like the Windows Azure manage website):

```javascript
if (settings.port !== undefined) {
	var elementName = settings.port.substring(8);

	var $self = $(this);

	$self.find('#' + elementName).each(function () {
		var $inputControl = $(this);

		if ($inputControl.attr('data-val-remote') !== undefined) {
			$inputControl.addClass('validation-pending');
		}
	});
}

```