Minor reveal fix - only preallocate unreveal data for existing map blocks
Update to 0.40.11, fix a few devel plugins to build again
Fix 3dveins crashing because of trees and malformed biome data.

The sky in the latest versions has uninitialized biome data, which
made the plugin crash on invalid vector index access. Also, trees
on ground may still have wrong geolayer inside them like obsidian.