Support full POSIX-style time zone: EST+3, PST-3, etc.

We probably support a superset of the spec, but I don't have the spec
 to confirm this.
Update regression tests to include tests for this format.
Fix single-space typo in printed message in regress.sh.

src/test/regress/regress.sh

 #!/bin/sh
-# $Header: /cvsroot/pgsql/src/test/regress/Attic/regress.sh,v 1.44 2000/03/14 23:06:55 thomas Exp $
+# $Header: /cvsroot/pgsql/src/test/regress/Attic/regress.sh,v 1.45 2000/03/16 14:37:33 thomas Exp $
 #
 if [ $# -eq 0 ]; then
 	echo "Syntax: $0 <hostname> [extra-tests]"