message: Array: add front() and back() functions to match std::vector interface
diff: @@ -631,6 +631,42 @@ public:
  /// \overload
  ConstArrayIterator end() const { return ConstArrayIterator(size(), this); }
  + /*!
  + * \brief Returns a reference to the first element in the Array.
  + *
  + * \pre array.empty() == false
  + */
  + T& front()
  + {
  + assert(!empty());
  + return *begin();
  + }
  +
  + /// \overload
  + const T& front() const
  + {
  + assert(!empty());
  + return *begin();
  + }
  +
  + /*!
  + * \brief Returns a reference to the last element in the Array.
  + *
  + * \pre array.size() > 0
  + */
  + T& back()
  + {
  + assert(!empty());
  + return *(end() - 1);
  + }
  +
  + /// \overload
  + const T& back() const
  + {
  + assert(!empty());
  + return *(end() - 1);
  + }
  +
  /*!
  * \brief Shrink the capacity to be equal to the size.
  */
  