Allow validation across all inputs with same name

The following piece of code in jquery.validate.js, `elements()` function, explicitly ignores all elements with the same name (except for the first)

```javascript
...
// select only the first element for each name, and only those with rules specified
if ( this.name in rulesCache || !validator.objectLength($(this).rules()) ) {
  return false;
}
...
```

IMO, we should rather apply the same validation rules for the elements with the same name. For which the modified piece of code would be:

```javascript
elements: function() {
	var validator = this,
		rulesCache = {};

	// select all valid inputs inside the form (no submit or reset buttons)
	return $(this.currentForm)
	.find("input, select, textarea")
	.not(":submit, :reset, :image, [disabled]")
	.not( this.settings.ignore )
	.filter(function() {
		if ( !this.name && validator.settings.debug && window.console ) {
			console.error( "%o has no name assigned", this);
		}

		// select this element if this has the same name as one in cache (may be was dynamically added)
		if ( this.name in rulesCache ) {
			if ( !validator.objectLength($(this).rules()) ) {
				$(this).rules('add', rulesCache[this.name]);
			}
			return true;
		}

		// select only the element with rules specified
		if ( !validator.objectLength($(this).rules()) ) {
			return false;
		}
		
		// Add rules to the cache
		rulesCache[this.name] = $(this).rules();
		return true;
	});
},
```

What this also makes possible is, if inputs are dynamically added (in case where multi-inputs exist), the same validation would apply to those too.