pgsql: Add options to force quoting of all identifiers.

Log Message:
-----------
Add options to force quoting of all identifiers.

I've added a quote_all_identifiers GUC which affects the behavior
of the backend, and a --quote-all-identifiers argument to pg_dump
and pg_dumpall which sets the GUC and also affects the quoting done
internally by those applications.

Design by Tom Lane; review by Alex Hunsaker; in response to bug #5488
filed by Hartmut Goebel.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        config.sgml (r1.298 -> r1.299)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/config.sgml?r1=1.298&r2=1.299)
    pgsql/doc/src/sgml/ref:
        pg_dump.sgml (r1.117 -> r1.118)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_dump.sgml?r1=1.117&r2=1.118)
        pg_dumpall.sgml (r1.82 -> r1.83)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/pg_dumpall.sgml?r1=1.82&r2=1.83)
    pgsql/src/backend/utils/adt:
        ruleutils.c (r1.328 -> r1.329)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/ruleutils.c?r1=1.328&r2=1.329)
    pgsql/src/backend/utils/misc:
        guc.c (r1.564 -> r1.565)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc.c?r1=1.564&r2=1.565)
        postgresql.conf.sample (r1.293 -> r1.294)

(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/postgresql.conf.sample?r1=1.293&r2=1.294)
    pgsql/src/bin/pg_dump:
        dumputils.c (r1.56 -> r1.57)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/dumputils.c?r1=1.56&r2=1.57)
        dumputils.h (r1.29 -> r1.30)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/dumputils.h?r1=1.29&r2=1.30)
        pg_dump.c (r1.582 -> r1.583)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_dump.c?r1=1.582&r2=1.583)
        pg_dumpall.c (r1.134 -> r1.135)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_dumpall.c?r1=1.134&r2=1.135)
    pgsql/src/include/utils:
        builtins.h (r1.351 -> r1.352)
        (http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/builtins.h?r1=1.351&r2=1.352)