Dev fix: The flatten() method should only flatten 2D arrays, and not

1D arrays.

- The method implemented isn't actually 100% perfect - if you mix arrays
  and scalars, then the behaviour is undefined. But that shouldn't
  happen in DataTables. Will look into it further, though

.datatables-commit-sync

@@ -1 +1 @@
-e36896eb799e0f3f1173ce3558bca8a8d222a08f
+24c30064ce0ef343caf702b3df0de7b4b96d1d1b

media/js/jquery.dataTables.js

@@ -6521,9 +6521,11 @@
 	
 		flatten: function ()
 		{
-			var a = this.reduce( function ( a, b ) {
-				return a.concat( b );
-			} );
+			var a = this.length && $.isArray( this[0] ) ?
+				this.reduce( function ( a, b ) {
+					return a.concat( b );
+				} ) :
+				this;
 	
 			return new _Api( this.context, a );
 		},