added support for ambientlight, pointlight, directionallight, and distantlight to tutorial06
added source of random number generator
Merge branch 'devel' into swoop
modified init of random generator
tutorial03/06 also start with no obj file specified, bugfix in distantlight
better choice of different BRDF components in tutorial06
ambient light can be sampled by sampling light or brdf
bugfix in shading normal interpolation
using original code from paper as random number generator
fixed calculation of nearX/Y/Z, have to get calculated based on ray.rdir and not ray.dir
removed FIX_RAYS mode, did never really work
renamed builder2 to builder
merge