Blender Git Loki

Make custom B/Mesh deleters for clean syntax

Fix build error

Merge local branch for importer into soc-2020-io-performance

Merge branch 'master' into soc-2020-io-performance

Use custom creators and deleters for Mesh and BMesh

Avoid freeing meshes allocated by Guarded allocated by unique_ptr

Mark OBJRawObject const in add_object_to_parent.

Add add_polygon_from_verts and add_bmvert to OBJBmeshFromRaw

Rename OBJMeshToBmesh to OBJRawToBmesh

Use better memory management for intermediate meshes.

Removed extra vertices in the new bmesh

Also considering to use `BM_mesh_bm_to_me_for_eval` to avoid
time spent in `BM_mesh_bm_to_me` for mesh data not required for OBJ.
So some commented code is present.

Commit a basic working importer, with some extra-to-be-removed code.

Merge branch 'master' into soc-2020-io-performance

Merge branch 'master' into soc-2020-io-performance

Use short for tot_col: total materials in an object.

Grammar fixes in comments.

Merge branch 'master' into soc-2020-io-performance

Support modifiers' render and viewport properties

Add null check for poly_smooth_groups array.

Merge branch 'master' into soc-2020-io-performance

Support multiple smooth groups and bitflags

For uniformity, removed `const MPoly &mpoly` from `write_vertex_groups`
and `write_poly_material`, and replaced it with poly_index. And use
`get_ith_poly` to get the polygon needed.

Removed `is_shaded_smooth`. It was wrong to compare an object level
flag with a polygon level flag. Replaced its usage with
`tot_smooth_groups()`.