get list of material IDs from vrmesh

[hypotheticalinc]

I understand why materials are not exported into vrmesh files, but it would be nice to be able to put an existing vrmesh into a scene and figure out what material IDs it already has and which pieces have which ID.

Adding a new list box next to the "object name list" and "object id list" for "material id list" would be very handy.