Saxon 9.6 Parameter Tunneling

This pull request aims to address some issues surrounding parameter tunneling in Saxon 9.6. Changing `tunnel="yes"` to `tunnel="no"` in 8df65cd059e3b82775f16361c56d5d8b24f6caf0 seemed to have unintentionally stripped a `<div class="reference">` from the output html document, thereby breaking the div expansion.

This has been tested with Saxon 9.5 and 9.6 and *seems* to work, but I'm unsure of the consequences of applying `tunnel="yes"` all over the place :)