Blender Git Loki

MOD_UVWarp: switch from OMP to BLI_task.

Usual 10%-15% speedup. Note that here OMP was rather erratic, with typical
timing about 10% slower than BLI_task, but having some 'burnouts' (~10% of times)
were it would be over ten times slower than usual... BLI_task looks much more stable.