PhysicsWorld::Raycast is a 1cm sphere sweep in disguise #17

Raycast delegates to SphereSweep with a hardcoded 0.01f radius (PhysicsWorld.cpp:299), so every ray is fat by a centimeter and grazing hits report on surfaces a true ray would miss. DynamicAABBTree::RayCast exists and is exercised by nothing. Either wire the real ray query or document the radius and take it as a parameter.