started on implementing csg intersectables
Fixed csg plane
wrote large parts of csg node
not normalizing ray directions anymore
added csgsphere and test for it
removed unused testutil, added benchmark tests for intersections
added performance tests for csg elements
returning now cleaned version of combined intervals
added constructor and test
made new test scene for csg objects, more cleanup for tests
Using now references to interval boundaries
pushed around some more code
added cube
solid is now directly a shape