message: Docs for Quaternion added
diff: @@ -97,13 +97,28 @@ public:
  float z; /**< @brief Quaternion entry 3 also denoted as d. */
  };
  - Quaternion() : a{0.0f} {};
  - Quaternion(float val) : a{val} {};
  - Quaternion(float w_, float x_, float y_, float z_) : w(w_), x(x_), y(y_), z(z_){};
  - float operator[](int i) const { return a.at(i); };
  - float& operator[](int i) { return a.at(i); }
  + Quaternion() : a{0.0f} {}; /**< @brief Constructor */
  + Quaternion(float val) : a{val} {}; /**< @brief Constructor */
  + Quaternion(float w_, float x_, float y_, float z_) :
  + w(w_),
  + x(x_),
  + y(y_),
  + z(z_){}; /**< @brief Constructor */
  +
  + float operator[](int i) const { return a.at(i); }; /**< @brief Operator [] */
  + float& operator[](int i) { return a.at(i); } /**< @brief Operator &[] */
  +
  + /**
  + * @brief Cast to float C-style float array
  + */
  operator float*() { return a.data(); };
  + /**
  + * @brief Cast to float array
  + */
  operator std::array<float, 4>&() { return a; };
  + /**
  + * @brief Cast to float array
  + */
  operator std::array<float, 4>() { return a; };
  private:
  