Disable transparency by default, switch back to greedy mesher

The real solution for transparency is to use something like
https://github.com/mikolalysenko/ao-mesher - see
https://github.com/deathcap/voxel-mesher - example in
https://github.com/deathcap/game-shell-voxel - porting to use on branch
https://github.com/deathcap/voxel-engine/tree/ndarray (the transgreedy
mesher + voxel-texture-shader is too slow and has rendering bugs).