Unpack 8-byte unsigned long long integers.
Work on updating the handler for the SXAddlInfo record.

This is still work in progress.

Also print raw bytes as characters for each record.  This helps detect
string bytes without having to write handlers.

Also, shorten the descriptions of some records to keep them fit within
76 char width.  We don't need to be verbose here; as long as we use the
same record names as in the spec we can look them up if needed.
Some notes about how we organize record list & more description for FEATURE11.