Function initialize

include/tabulate/optional_lite.hpp:1233–1237

  void this_type_does_not_support_comparisons() const {}

  template <typename V> void initialize(V const &value) {
    assert(!has_value());
    contained.construct_value(value);
    has_value_ = true;
  }

#if optional_CPP11_OR_GREATER
  template <typename V> void initialize(V &&value) {