function multiplyScalar(out, a, b) {
  out[0] = a[0] * b;
  out[1] = a[1] * b;
  out[2] = a[2] * b;
  out[3] = a[3] * b;
  out[4] = a[4] * b;
  out[5] = a[5] * b;
  out[6] = a[6] * b;
  out[7] = a[7] * b;
  out[8] = a[8] * b;
  out[9] = a[9] * b;
  out[10] = a[10] * b;
  out[11] = a[11] * b;
  out[12] = a[12] * b;
  out[13] = a[13] * b;
  out[14] = a[14] * b;
  out[15] = a[15] * b;
  return out;
}
Multiply each element of the matrix by a scalar.

@param {mat4} out the receiving matrix
@param {mat4} a the matrix to scale
@param {Number} b amount to scale the matrix's elements by
@returns {mat4} out