add Plane.intersectLine with unit tests.
expand Matrix3 with set, identity, copy, multiplyScalar, deteminant, clone;  Matrix3/4.getInverse will now optionally throw an exception; start Matrix3/4 unit tests
remove debugging log message from Matrix3.getInverse
optimize determinant calculation in Matrix4.getInverse()
add credits.
fix Raycaster instance references to use Raycaster.ray
This is the lowlevelrenderer
update lowlevel renderer
expand tests of Matrix3 and Matrix4 inverse functions.
Simpler CONTRIBUTING suggested by @WestLangley. Fixes #2847.
Docs: Updated structure.
Merge remote-tracking branch 'maxogden/pointerlock-bugfix' into dev
update webglrenderer2 to get the exmaples working
make webglrenderer2 work for bufferGeometry and ribbons
make uniform2 work and make webglrenderer again usable
reorder Matrix4.determinant to match order used by Matrix4.getInverse
pull out common factors of Matrix4.determinant.
add another determinant unit tests which utilizes every value of the matrix.
reorder based on @WestLangley suggestion.
remove unused variables from Raycaster.