BLD changes from Apr 7 to Apr 10

The color coded diff in the Apr 10 draft was unusable because the main
difference was moving section 2 (the BLD-as-specialization-of-FLD) to
the end, and this diff program doesn't understand section-moves.  I've
re-done the diff to show all changes _other than the move_, so folks who
reviewed the Apr 7 draft can see the small changes.

   http://www.w3.org/2005/rules/wg/draft/ED-rif-bld-20080410/

Remember -- we're planning to vote on publishish BLD, FLD, and RDF-OWL
on Tuesday.

     -- Sandro