Models are flipped on the x-axis

[Utsira]

If you compare how an asymmetrical model appears in MV with Bevy, when loading via bevy_vox_mesh, the model is flipped on the x axis.

eg: the monu1 model that ships with MagicaVoxel as viewed in MV:

Same model in bevy:

I believe the fix for this is to change the linearisation in voxel.rs lines 35-37 to:

        let index =
            model_shape.linearize([model.size.x - voxel.x as u32, voxel.z as u32 + 1, voxel.y as u32 + 1])
                as usize;

this seems like the right place to flip the x axis, as this is where the Y and Z axes get swapped

[Game4all]

I would gladly accept a pull request to fix this!