Make ships check for walls when doing leave

[GoZelda]

because i don't want to get stuck on shipyard wall again

[Satrek2000]

While we're at it (well, has to do with ships: add something that keeps marking runes from being accepted on deep water - it's a bugger to sail through such waters, south Forest and just right from Hotaru for example. I know that magic missile/missile swarm has a chance to take them out, but I casted the swarm about 10 times and didn't destroy a single one...