Ditch work on scene numbers

Revert back to commit 9b3a7c1e467516ced13c93954e5f8ceb6fc43dc4 in
effect.  ("git checkout 9b3a7c1e467516ced13c93954e5f8ceb6fc43dc4 .")

Shooting scripts have scene numbers.  Spec scripts don't.  See the
example at http://www.oscars.org/awards/nicholl/scriptsample.pdf for
example.  I doubt anyone will use this to write a shooting script,
only a spec script.  (Would that more industries besides software
development used Git.)