Migrate sources to Mercurial. Update links etc.

vcproj build target only for cc=msvc, fix sdl-config

new build target 'vcproj' - generate Visual C++ Studio project files; fix GCC warnings in intersect_packet()

build script: updated for latest SCons, moved config.h to build/, help and clean targets does not run configure any more, fixed GCC check, added check for zlib

add sections about demos to README update doxygen comments

added bench.py demo which prints tree build and render times added Vertex to python binding, NormalVertex is now its subclass

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

build script fixes, add ldflags build option update and enhance demos fix bug in 4x grid oversampling warn if writePNG called while compiled without libpng make shapes in ShapeList const and add many other const needed due to snowball effect slightly optimize Camera::makeRayPacket using _mm_shuffle_ps make Vector SIMD vectorization disabled by default (causes problems) fix bug in implicit reflection of transmissive surfaces, when surface's reflection parameter is set to zero

update README update Doxygen docs scons option 'msvc' changed to 'mingw' as msvc is default and mingw must be turned on explicitly

more build script tuning make all float constants single precision solve many warnings from msvc and gcc with various -W... flags add common.cc file for dbgmsg() function witch apparently cannot be inlined fix python module building with msvc, add manifest file handling remove forgotten RenderrowData class add stanford models download script for windows (.bat)