Igloo Changes

While igloos are a fun little addition, they need some changes, as they are kind of boring right now;

*Igloos that generate on land will always have a basement

*Igloos will now generate on the ice of frozen rivers and frozen oceans. However, due to having water underneath them, they will never have basements.

*Igloos will spawn with a snow golem inside the main part.

*Villagers in the dungeons have special trades.

This will improve them and make players more excited when an igloo is found.