Load/save auxiliary functions

// global functions

template <typename T>
void nanoflann::save_value(
    FILE* stream,
    const T& value,
    size_t count = 1
    );

template <typename T>
void nanoflann::save_value(
    FILE* stream,
    const std::vector<T>& value
    );

template <typename T>
void nanoflann::load_value(
    FILE* stream,
    T& value,
    size_t count = 1
    );

template <typename T>
void nanoflann::load_value(
    FILE* stream,
    std::vector<T>& value
    );