added Python binding for material.h classes
added raytracermodule.h header file for declarations
updated car.py demo
added texture.py demo (based on spheres_glass.py)
all remaining 'centre' changed to more common 'center'
added some more const's to material.h
Bugs==== * Mingw + SSE does not workFuture Plans============ * UV texturing * PlanarMap should allow to choose normal axis * Container should implement Shape interface to allow building hierarchies * Container should allow local space transformations * generalization: Camera "shader" (ray generator), surface shader and maybe light & background shaders * put everything into a namespace * stochastic oversampling * absorbtion of refracted rays in dense materials (can be computed using shape distance and some 'absorbance' constant)