remove transactions
	use create or replace function
	make formatting consistent
	set search patch on first line

Add documentation on modifying *.sql to set the search patch, and
mention that major upgrades should still run the installation scripts.

Some of these issues were spotted by Tom today.

contrib/pgbuffercache.

Greg Smith

improve examples.

Mark Kirkwood

particular get rid of single quotes around language names and old WITH ()
construct.

for efficiency's sake.  Mark Kirkwood.