About math3d

This library is modified from the math module of three.js

What have been changed

you could jump to the corresponding commit by the links

• NDC is converted from OpenGL space to Metal
• new interfaces to apply translation or rotation to Matrix4
• replace Matrix4.makePerspective( left, right, top, bottom, near, far ) with Matrix4.makePerspective( fov, aspect, near, far ) and add Matrix4.makeFrustum( left, right, top, bottom, near, far )