MeshGL64 tests, bindings, and deprecate Mesh

[pca006132]

We should get this done before v3.0.

[pca006132]

@elalish We need to somehow get vertex pseudonormals in the meshgl output for our tests. I think CalculateNormals is actually giving us the face normal (duplicated property vertices?) for sharp edges, which is not very useful for our tests.

[pca006132]

Also, I'm thinking if we should make the indices 64 bit, so we can slowly use 64-bit integers internally.

[elalish]

Let me look into those tests - I'll do that next. I'd guess some just need to be rethought.

Are you thinking 64 bit ints just for MeshGL64?

[pca006132]

Are you thinking 64 bit ints just for MeshGL64?

Yes.