Create hierarchy from multi LoDs OBJ models

[LorenzoMarnat]

--as_lods allows to create a tileset from several OBJ files, where the first file is the least detailled model and the last file the most detailled. It will create a refinement hierarchy from the least detailled model to the most detailled model.

In this example, model_0.obj is the least detailled model:

obj-tiler -i model_0.obj model_1.obj model_2.obj --as_lods --geometric_error 1 4 8

If OBJ files are in the correct order in the folder:

obj-tiler -i <path>\objs\ --as_lods --geometric_error 1 4 8