Ignoring .DS_Store on OSX
Using a dummy RWLock
Working camera classes
Added missing DifferentialGeometry.compute_differentials()
New class: Filter
New class: BoxFilter
New function: concentric_sample_disk()
Allow constructing a Vector from a Point
Fixed Scene.intersect() method
Dummy implementation of RNG, as a wrapper around random module
Fixed GeometricPrimitive's get_bsdf and get_bssrdf methods
Fixed sampler
Added error checkings in Intersection class
Fixed SamplerRenderer
New class: RandomSampler
Test scene is starting to work
Working version of ImageFilm, removed internal usage of Pixel class for now
Added conversions to and from XYZ color space, and arithmetic operations between colors
Dummy implementation of Whitted as Materials are not yet implemented, return Spectrum(1.0) on any impact.