Add oldindex property to sortupdate event data

knowing the old index is a useful feature for using this in an MVVC application, since the underlying array can be spliced instead of having to be rewritten.

AngularJS example:

```javascript
function SortableCTRL($scope) {
	$scope.sortableArray = ['One', 'Two', 'Three'];
	
	$scope.sortupdate = function(e, data) {
		var start = data.oldindex,
			end   = data.item.index();
		
		$scope.sortableArray.splice(end, 0,
			$scope.sortableArray.splice(start, 1)[0]);
		
		$scope.$apply();
	};
	
	setTimeout(function() {
		$('#sortable')
			.sortable()
			.on('sortupdate', $scope.sortupdate);
	});
}```
during ‘destroy’, remove event handlers added with ‘.on('sortupdate', …)’
Merge branch 'patch-1'
Update jquery.sortable.js

Added option for placeholder
- added custom markup for placeholder as option, useful when using with tables.
Example :
	// JS CODE
	$('table.data tbody').sortable(
	{  
		items: 'tr' ,
		placeholder : '<tr><td colspan="7">&nbsp;</td></tr>'
	}) ;

	// CSS STYLE FOR TR > TD
	.sortable-placeholder td
	{
		background:#FFFEB8;
		height:100px;
		width:100%;
		
	}
Support vertical lists of variable height by defining a dead zone when hovering over larger items.
add reload method
Fix false negative bug when dropping onto same index in new container.
Improved handling of handles such that sub elements can be interacted with.
Improved placeholder sizing for horizontal sorting.
Updated README.md
add reload method
Merge https://github.com/rodolfospalenza/html5sortable into HEAD
Update README
Update README
Merge https://github.com/bistoco/html5sortable
Update README
Merge https://github.com/flying-sheep/html5sortable
Update README
Tabs to spaces and fix for options being reset when doing reload.
AngularJS directive.
Update documentation.