Scene3D

This is the PBRT -> ISET interface. 

We use a modified (forked) form of PBRT that is in 

  https://github.com/ydnality/pbrt-v2-spectral/tree/spectral

which is derived from the master repository

  https://github.com/ydnality/pbrt-v2-spectral

The Scene3D repository contains 

	* Matlab files that call PBRT
        * Some PBRT data (examples)
	* Matlab files that read PBRT output and convert them to ISET objects