pgsql: Use E'' strings internally only when standard_conforming_strings

Log Message:
-----------
Use E'' strings internally only when standard_conforming_strings =
'off'. This allows pg_dump output with standard_conforming_strings =
'on' to generate proper strings that can be loaded into other databases
without the backslash doubling we typically do. I have added the
dumping of the standard_conforming_strings value to pg_dump.

I also added standard backslash handling for plpgsql.

Modified Files:
--------------
pgsql/src/backend/utils/adt:
quote.c (r1.18 -> r1.19)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/quote.c.diff?r1=1.18&r2=1.19)
ruleutils.c (r1.221 -> r1.222)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/ruleutils.c.diff?r1=1.221&r2=1.222)
pgsql/src/bin/initdb:
initdb.c (r1.114 -> r1.115)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/initdb/initdb.c.diff?r1=1.114&r2=1.115)
pgsql/src/bin/pg_dump:
dumputils.c (r1.27 -> r1.28)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/dumputils.c.diff?r1=1.27&r2=1.28)
dumputils.h (r1.15 -> r1.16)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/dumputils.h.diff?r1=1.15&r2=1.16)
pg_backup_archiver.c (r1.129 -> r1.130)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_backup_archiver.c.diff?r1=1.129&r2=1.130)
pg_dump.c (r1.433 -> r1.434)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_dump.c.diff?r1=1.433&r2=1.434)
pg_dumpall.c (r1.75 -> r1.76)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_dumpall.c.diff?r1=1.75&r2=1.76)
pgsql/src/bin/psql:
describe.c (r1.134 -> r1.135)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/describe.c.diff?r1=1.134&r2=1.135)
large_obj.c (r1.41 -> r1.42)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/large_obj.c.diff?r1=1.41&r2=1.42)
pgsql/src/bin/scripts:
createdb.c (r1.16 -> r1.17)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/scripts/createdb.c.diff?r1=1.16&r2=1.17)
createuser.c (r1.27 -> r1.28)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/scripts/createuser.c.diff?r1=1.27&r2=1.28)
pgsql/src/include:
c.h (r1.200 -> r1.201)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/c.h.diff?r1=1.200&r2=1.201)
pgsql/src/interfaces/ecpg/ecpglib:
execute.c (r1.45 -> r1.46)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/ecpglib/execute.c.diff?r1=1.45&r2=1.46)
pgsql/src/pl/plpgsql/src:
gram.y (r1.88 -> r1.89)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/gram.y.diff?r1=1.88&r2=1.89)