TRUNCATE, VACUUM, ANALYZE privileges

Greetings,

  The following patch implements individual privileges for TRUNCATE,
  VACUUM and ANALYZE.  Includes documentation and regression test
  updates.  Resolves TODO item 'Add a separate TRUNCATE permission'.
  Created off of current (2005/01/03) CVS TIP.

  At least the 'no one interested has written a patch' argument is gone
  now, fire away with other comments/concerns. :)

      Thanks,

        Stephen