Blender Git Loki

Implemented SSR :
- Still pretty rough implementation does only works with sharp glossy shader
- No Glossy reflection
- 2 algorithm but only one acheive decent results the other needs to be debuged.

Changed pbr settings location :
- They are now stored in structs like the FX options

Merge branch 'asset-engine' into asset-experiments

Merge branch 'id-remap' into asset-experiments

Conflicts:
source/blender/windowmanager/intern/wm_files_link.c

Merge branch 'master' into asset-experiments

Merge branch 'master' into asset-engine

Lib relocate/reload: serious rework of code.

Idea here is to both factorize it seriously (reload and relocate are very similar, let's
avoid as much as possible twice the same code...), and make new `lib_relocate_do()`
much more flexible - now it should be able to reload individual IDs as well
(plan is to use it to reload assets in relelvant branch too).

Merge branch 'master' into id-remap

Merge branch 'master' into asset-engine

Merge branch 'master' into id-remap

Merge branch 'master' into alembic_basic_io

Fix for mesh vertices not being written when exporting the object to a
different coordinate system.

Merge branch 'asset-engine' into asset-experiments

Amber: Fix load_pre not using correct repo!

Merge branch 'asset-engine' into asset-experiments

Merge branch 'id-remap' into asset-experiments

Merge branch 'master' into asset-experiments

Amber: fix missing '..' parent dir entry when inside a repo.

Change how Amber (and all other engines) are expected to work.

So far, we were accepting the idea of several repositories per asset engine (e.g. different
directories in case of Amber). However, if this works OK during listing/initial linking,
it makes things way more complicated later in asset management, since asset uuid is no more
enough to unically indentify an asset!

Now an asset UUID is assumed to be really unique inside an asset engine.

For Amber, we 'salt' assets' uuids with new repo uuids (both being only 2 ints long now),
and keep a config 'cache' of mapping repo uuid -> path to repo.

Cycles: Implement re-fitting of curve BVH

Internally re-fitting will fall back to AABB nodes which is not fully
efficient but is fast enough to rebuild BVH.

Probably for viewport we can use curve BVH but disable unaligned
heuristic to reduce preparation time.

Cycles: Optimize shadow rays intersection