Modif in MeshData.hx

During tests with the iron example,
I got a problem with the loop near line 35 of the MeshData.hx that is

For(ind in raw.index_arrays)

Then I tested with modifying it with raw.mesh.index_arrays and got problem with dynamic not accepted.

I saw also that in a preceding version of this file, this was too like that.

Do you have an idea for this ?