example:
```
{
"_xvk_surface_id" "489"
"_xvk_texture" "#maps/test_material.bsp:debug_normal1.mip"
}
```
if _xvk_texture is empty, then the surface will be deleted
surfaces can be deleted or their
- look for materials in:
- pbr/materials.mat
- pbr/models/materials.mat
- pbr/wadname.wad/materials.mat
- pbr/maps/mapname.bsp/materials.mat
- all paths are relative to their materials.mat, except for ones that begin with '/', which are relative to `pbr` dir
pbr dir should be placed in modname dir, e.g. 'valve'
#155
1. make sure that it can find studio textures by name exactly (no wad or
other weird prefixes necessary)
2. do not apply HACK_reflective to chrome that already has a patched
material
