Shipyard Expansion v0.7.3

• added an alternate deck arrangement to the cog, with a flatter foredeck and some hatches
• added a tiller option to the kakam (tiller instead of wheel)
• load-time optimizations. should make the game start faster
• added a system to keep saves from being broken by the base game adding new boat parts (you'll need to load your saves and re-save them before loading the new game version)