v1.6

• Added Raytracing Renderer
• Updated materials for Raytracing, added HasRaytracingGlass, HasRaytracingMirror interfaces
• Refactored all math classes - improved performance
• Refactored vectors - removed Vector interface
• Refactored renderers, added AbstractRenderer class
• Refactored Curve and Path classes
• Refactored PlaneBufferGeometry and PlaneGeometry classes - parameters width and height are double now.
• Added BoxHelper
• Added FaceNormalsHelper
• Added GridHelper
• Added PointLightHelper
• Added VertexNormalsHelper
• Added WireframeHelper
• LineDashedMaterial extends LineBasicMaterial now