merge pixmap handling from sampler, material.h and ccdemos's image module to new Pixmap class
add check for PNG library, allow writing PNG file from a Pixmap
simplify demos using new methods from Sampler and Pixmap
Bugs
====
* (none known)
Future Plans
============
* generalization: Camera "shader" (ray generator), surface shader and maybe light & background shaders
* namespace
* Python binding for all classes
* stochastic oversampling
* absorbtion of refracted rays in dense materials (can be computed using shape distance and some 'absorbance' constant)
* implement efficient AABB-ray intersection using Plucker coordinates
New Classes?
============
scene.h -- Scene, ...
reader.h -- Reader, WavefrontReader
wf = new WavefrontReader()
wf.setContainer(top)
wf.setTransform(monkey_pos_matrix)
wf.read("monkey.obj")
// more transform&reads
destroy wf
Scene scene -- container with shapes, a camera and lights
scene = new Scene()
scene.setCamera(new Camera(eye, u, v, p))
scene.addLight(new PointLight(pos, color))
rt.setScene(scene)
rt.render(w,h)