More CRAM 4 shuffling

- BYTE is now the same ID as the old EXTERNAL, given it's identical.
  But we refer to it as BYTE for clarity sake.

- Removed sint vs uint in data series types as it's no longer
  necessary to bake this into the specification.

- Moved the Data Series format text to later on and merged with the
  other tables, so the concepts and formats are introduced at the same
  point.

Author: jkbonfield