message: cast: Add `std::shared_ptr` casting.
diff: @@ -97,5 +97,13 @@ namespace elle
  p.release();
  return std::unique_ptr<T>(res);
  }
  +
  + /// Unconditionnaly cast \a p to type \a T.
  + template <typename U>
  + static std::shared_ptr<T>
  + compiletime(std::shared_ptr<U> const& p)
  + {
  + return std::static_pointer_cast<T>(p);
  + }
  };
  }
  