Implemented Grid Precomputation
Kernel: gridIndex, t updates
Acceleration enabled
Consolidated some operations
Find stepAxis using bit operations
Fixed deltaT implementations
Merge branch '2a' of https://github.com/yghannam/RayTracing into 2a

Conflicts:
	YazenGhannam_CAP6721_RayTracer.html
Fix deltaT calculations
Support multi-node models; import gl-matrix.js
ShapeData includes material data; begin refraction rays