Fix for fast simulation

[SanggunLee]

Im fixing bottleneck of carla simulation.

Im a fullstack (from linux kernel to deep learing dev) sw engineer.
I can do inspect and fix the bottlenecks.

this page for log.

[SanggunLee]

1. Thread
2. Memory
3. physx
4. overlap

I found the bottlenecks and I am working on the problem.