Build the renderer from a config map
Build the scene from a config map

Also add comments about hollow sphere scene.
Read config from file
Communicate sample range from sensor to sampler
Make sensors part of the scene

Add GetSensors() function to Primitive.

Add PointPrimitive.

Add "black" Spectrum type.
Add hollow sphere with center light example
Add Cornell box example
Implement PerspectiveCamera sensor and use it in Cornell box example
Render using multiple goroutines
Add flag to control number of render jobs
Add flag to write a CPU profile
Implement blocking for IndependentSampler
Add support for specifying a crop window for PerspectiveCamera
Implement Rect shape
Use a rect for the back wall in the Cornell box example
Use a rect for the front wall in the Cornell box example
Use a rect for the top light in the Cornell box example
Use a rect for the floor in the Cornell box example
Use a rect for the left wall in the Cornell box example
Use a rect for the right wall in the Cornell box example