* Fixed LODs for shadow meshes.
* Added a merging step before simplification. This helps with tesselated
meshes that were previously left untouched. The angle difference at
wich edges ar considered "hard" can be tweaked as an import setting.
* LODs will now start with the highest decimation possible and keep
doubling (approximately) the number of triangles from there. This
makes sure that very low triangle counts are included when possible.
* Given more weight to normal preservation.
* Modified MeshOptimizer to report distance-based error instead of
including attributes in the reported metrics.
* Added attribute transference between the original mesh and the
various LODs. Right now only normals are taken into account,
but it could be expanded to other attributes in the future.
