HDSTRACE: Improve control of text width and prevent misplaced wrapping.

- Added WIDTH parameter to allow more control over the width.
- Default WIDTH to the terminal width.
- Adjust the message-system output size to accommodate chosen width to
  prevent premature line wrapping.
- Only access deprecated Parameter WIDEPAGE if WIDTH is undefined.
- Update start and reference section of SUN/102.  (It needs a fair
  amount of work to use modern LaTeX and hypertext, plus remove VMS
  stuff.)
- Increment to Version 1.2-4.
HDSTRACE: Prologue tidying.
HDSTRACE: Some tidying and updating of SUN/102 contents.