Clean up LAMP, LIGHT, vec, cpvec, mat, and matNxN classes.

- Remove vec component-wise multiplication, and division.
- Clean up constructor definitions, especially copy constructors for
  LAMP (Chapter 10), LIGHT module, vec, cpvec, mat, and matNxN
  classes/class templates.
- Add back quat_build_w().
- Improve LAMP/LIGHT assignment operators.