Merged changes in the trunk up to revision 50829.

Conflicts resolved:
source/blender/blenloader/intern/readfile.c
source/blender/render/intern/source/convertblender.c
source/blender/render/intern/source/pipeline.c

Also addressed code inconsistency due to changes in the trunk revision 50628 (color
management with OCIO) and 50806 (UV project material).  OCIO-related changes are marked
OCIO_TODO as in some other files modified in revision 50628.

source/blender/python/mathutils/mathutils_geometry.c

@@ -46,8 +46,6 @@
 #include "BLI_math.h"
 #include "BLI_utildefines.h"
 
-#define SWAP_FLOAT(a, b, tmp) tmp = a; a = b; b = tmp
-
 /*-------------------------DOC STRINGS ---------------------------*/
 PyDoc_STRVAR(M_Geometry_doc,
 "The Blender geometry module"