RoyalMCPE

It maybe worth exporting [firstReplaceable](https://github.com/df-mc/dragonfly/blob/b191b9e4c23e961a9224e74492d229ad8f883a8b/server/block/block.go#L155) and [place](https://github.com/df-mc/dragonfly/blob/b191b9e4c23e961a9224e74492d229ad8f883a8b/server/block/block.go#L170) so that the end user doesn't have to copy the logic to add vanilla placement to their blocks.

Yeah trust me, I'm aware of the challenges. This is the third time I've looked into this. In the last year. I think I have a solution mapped out though....