Merge branch 'bb/update-unicode-table'

Simplify the procedure to generate unicode table.

* bb/update-unicode-table:
  update_unicode.sh: delete the command group
  update_unicode.sh: make the output structure visible
  update_unicode.sh: shorten uniset invocation path
  update_unicode.sh: set UNICODE_DIR only once
  update_unicode.sh: simplify output capture