WebGLRenderer: Added a way to access the full shader.
Updated builds.
RaytracerRenderer: @alteredq's improvements ^^
RaytracingRenderer: Avoid polluting the scenegraph.
Because, currently, WebGLRenderer also creates _modelViewMatrix things weren't working nicely in the editor.
Not sure about the "cache" naming though...
Updated raytracer example and added @alteredq's credit.
Raytracing example clean up.
BufferGeometry: Trying to prettify...
BufferGeometry: Safer check.
Updated builds.
WebGLRenderer: getShader to THREE.WebGLShader.
Updated builds.
WebGLShader: Simplified logic.
Updated builds.
WebGLRenderer: Moved builProgram to WebGLProgram.
Updated builds.
WebGLProgram: Save actual shader.
If needed, source is retrievable by doing  renderer.context.getShaderSource( material.program.vertexShader );
Updated builds.
Object3D: Setting matrixWorldNeedsUpdate to false by default. Fixes #4506.
Updated builds.
WebGLRenderer: Tweaked index0AttributeName handling. Fixes #4469.