code: function copy(v, dst) {
    dst = dst || new VecType(3);
  
    dst[0] = v[0];
    dst[1] = v[1];
    dst[2] = v[2];
  
    return dst;
  }
docs: Copies a vector.
  @param {module:twgl/v3.Vec3} v The vector.
  @param {module:twgl/v3.Vec3} [dst] vector to hold result. If not new one is created..
  @return {module:twgl/v3.Vec3} A copy of v.
  @memberOf module:twgl/v3