In integer sequences, format "see below" appropriately.
Update table of headers.
Editorial and bug fixes in optional

Removed optional<T>:: from description of constructors, destructors,
and assignment operators.
Add std:: to size_t for consistency in type traits synopsis.
Fix typo "mil[l]iseconds"
Fix "k -> ke" and formatting in complexity for a_tran.count(ke).
[sequences.general] Add missing angle brackets around dynarray header.