Precision 18 upgrades

I added a few things to make it easier to handle Reel Fun. I believe the year after my model, they added the blocks to lead the halyard to the cockpit. I copied this so I could raise the main without leaving the cockpit. I also added a "Tiller Tamer" to keep the tiller from flopping over if I let go of it or needed to go to the mast for any reasons.

The Porta Potti was added in case I had anyone on board who couldn't pee over the side :) Hopefully it won't see much use.