Clamped Box diagonal to zero in case of degenerate boxes
Initial work on more efficient Bvh construction
More work on improved Bvh building
Prepared Box to use Simd types as contents
Vectorized Bvh construction
Added missing include in Renderer
Removed unnecessary lodepng include in standalone
ThreadPool overhaul

- Implemented task groups, waitable tasks and completion callbacks
- Implemented parallel for
- Added global thread pool
- Added way to determine optimal thread count on the current machine
Optimized and parallelized minimum torsion normal computation
Implemented ThreadPool::yield to allow executing other tasks while waiting
Changed parallelFor to yield while waiting
Added convenience typedefs in SimdBool/SimdFloat
Initial commit of SIMD Vector header
Added vectorized bounding boxes
Refactored BinaryBvh to use new SIMD types
Implemented optimized parallel bvh construction

- Removed templatization on branch factor
- Refactored into separate files
- Moved construction methods into static functions to emphasize lack
of state
Changed setup_builds to remove vstudio folder without prompt
Minor fixes to compile with MSVC