Hey!

So, I figured I'd rather fix this issue ASAP. Thank you for bringing this to my attention. Turns out maxWorldHeight is a funny thing...

Here are the changes:

- Fixed a bug regarding maximum world height that messed up the grave generation when there was a block at height 319 (Overworld).
- Slightly improved search algorithm
- Now starts at the player's height and searches upwards only for the player's exact location.
- Old search for everything else.