All Shallow Water

All deep water tiles are marked as shallow water while still persist the deep water pixel, allowing the construction of bridges and piers across deep water tiles to connect multiple islands. The side effect is, all islands are now considered one island, making it impossible to include any AI kingdoms. Villagers and armies can now swim across the oceans as well. There is also no more guarantee for the game to generate at least one stone ore and one iron ore for each island. This mod does not work well with old save. UPDATE: fixed an issue that would cause all fish to extinct.