Update to 6.88

Upstream changes:
6.88  Sat Jun 28 13:14:00 BST 2014
    - BotAddressed: Handle being addressed with a prefixed @ or %

6.87  Sat Jun 21 15:08:32 BST 2014
    - Believe have resolved issues with online test

6.86  Fri Jun 20 11:12:06 BST 2014
    - Added more diagnostics to the online test

6.85  Thu Jun 19 10:19:07 BST 2014
    - Added some diagnostics output to the online test

6.84  Tue Jun 17 10:45:38 BST 2014
    - Plugman: store @$ or else it gets overwritten - Commit: 65ba2a4f3

(wen)