Revert "Sorting not needed here."

This reverts commit 60bb3147833bfe3bc45754cd63cefc4d2350253b.

The sorting is needed because of threads which have had their
shown/hidden changed since the last sort. Due to 'Anchor Hidden Threads'
these can be out of order.

src/General/Index.coffee

@@ -245,6 +245,7 @@ Index =
         'Hide'
       else
         'Show'
+      Index.sort()
       Index.buildIndex()
 
     mode: ->