Support calculating face normals when tessellating. When this is done before updating vertex normals it gives ~20% performance improvement. Now vertex normal calculation only needs to perform a single pass on the mesh vertices when called after tessellation. Extended versions of normal & looptri update functions have been added: - BM_mesh_calc_tessellation_ex - BM_mesh_normals_update_ex Most callers don't need to be aware of this detail by using: - BKE_editmesh_looptri_and_normals_calc - BKE_editmesh_looptri_and_normals_calc_with_partial - EDBM_update also takes advantage of this, where calling EDBM_update with calc_looptri & calc_normals enabled uses the faster normal updating logic.