Blender Git Loki

Do not include BKE_mesh.h in bmesh_class.h

We absolutely avoid such include unless totally mandatory, here we can
simply keep lnorspaces array a pointer in BMesh struct, and allocate it
on demand. Also, was breaking bmesh tests building.

Note: this totally breaks undo/redo, but previous code was utterly
wrong here as well (shallow copy of lnorspaces, ending up sharing whole
internal memory -> crash garanteed ;) ). Think we can skip that struct
for undo/redo for now at least, we can rebuild it in those cases imho...