Build 26580981

## Early access achievements

### New: achievements
- **Pioneer**: play ten hours during early access.
- **I'm a helper!**: send a bug report from the game menu during early access.
- **Better together**: play two hours of co-op during early access.
- **Through the updates**: play three different updates during early access.
- They can only be earned during early access. Play time from before this update doesn't count.

### Fixes
- Co-op: floating islands are now the same on every player's machine wherever the players are, so digging into an island far from the host comes out the same for everyone.
- Co-op: games on different versions of the world can no longer join each other (you would have ended up in different worlds). If you can't see a friend's game, make sure you both have the latest update.
- When a building placement is refused, the game now tells you why.