message: Add operator+(mat4,mat4)
diff: @@ -206,6 +206,18 @@ inline matrix<4, 4, T> matrix<4, 4, T>::translation(T const& x, T const& y, T co
  // Basic arithmetic
  //
  +template <typename T>
  +MATH_FUNC
  +inline matrix<4, 4, T> operator+(matrix<4, 4, T> const& a, matrix<4, 4, T> const& b)
  +{
  + return matrix<4, 4, T>(
  + a(0, 0) + b(0, 0), a(1, 0) + b(1, 0), a(2, 0) + b(2, 0), a(3, 0) + b(3, 0),
  + a(0, 1) + b(0, 1), a(1, 1) + b(1, 1), a(2, 1) + b(2, 1), a(3, 1) + b(3, 1),
  + a(0, 2) + b(0, 2), a(1, 2) + b(1, 2), a(2, 2) + b(2, 2), a(3, 2) + b(3, 2),
  + a(0, 3) + b(0, 3), a(1, 3) + b(1, 3), a(2, 3) + b(2, 3), a(3, 3) + b(3, 3)
  + );
  +}
  +
  template <typename T>
  MATH_FUNC
  inline matrix<4, 4, T> operator*(matrix<4, 4, T> const& a, matrix<4, 4, T> const& b)
  