Reworking spawn snowballs. It's a bit messy right now.
Still reworking the spawn snowballs, but they are better now. Classes instead of EntityType, with fewer casts and more typesafety. The enchanting table snowball is now its own class, and Feeeesh snowballs use the common code where appropriate (so they are rate limited).

I've also removed the lightning hack, so if we decide not to spawn for lack of space, we just do nothing. Customization is now done through methods that won't have to deal with nulls, so there's on need to always have an entity anymore.