Simplify adding rows to sortable tables

The `append` method can handle arrays, so there's no need to loop
through each element.

There's more to improve on this method, like the `asc` variable being
global to a table instead of depending on the current column, but for
now I'm only refactoring and maintaining the current behaviour.

app/assets/javascripts/table_sortable.js.coffee

@@ -13,10 +13,10 @@ App.TableSortable =
       table = $(this).parents("table").eq(0)
       rows = table.find("tr:gt(0)").not("tfoot tr").toArray().sort(App.TableSortable.comparer($(this).index()))
       @asc = !@asc
-      if !@asc
-        rows = rows.reverse()
-      i = 0
-      while i < rows.length
-        table.append rows[i]
-        i++
+
+      if @asc
+        table.append rows
+      else
+        table.append rows.reverse()
+
       return