Sortable: _intersectsWithPointer does not work for horizontal moves

Enviroment:

Windows 7, Chrome Version 31.0.1650.63 m

Discription:

Just use the sample demo: http://jqueryui.com/sortable/

Drag one item, and move horizontally over other item, the placeholder does not update unless you make a tiny vertical mouse move.

It seems that in line 570 of sortable.js in https://github.com/jquery/jquery-ui/blob/master/ui/jquery.ui.sortable.js

we should use:

: ( (verticalDirection && verticalDirection === "down") ? 2 : 1 );

rather than

: ( verticalDirection && (verticalDirection === "down" ? 2 : 1) );