Hi all!

Please get the latest version (2.53) from GitHub:
- material loading crashes are fixed (a crash still can rarely happen on terrain texture resizing, seems to be engine related, but will try to fix it too),
- billboard LOD added to vegetation, works with commercial and pro license (the old cross-shaped LODs are still available in obstacle_mdl/cross_lod folder for free and extra users, just overwrite files in obstacle_mdl with them),
- some lighting calculations are tweaked.