pgsql: Add "isodow" option to EXTRACT() and date_part() where Sunday =

Log Message:
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Add "isodow" option to EXTRACT() and date_part() where Sunday = 7.

Modified Files:
--------------
pgsql/doc/src/sgml:
func.sgml (r1.361 -> r1.362)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/func.sgml.diff?r1=1.361&r2=1.362)
pgsql/src/backend/utils/adt:
datetime.c (r1.176 -> r1.177)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/datetime.c.diff?r1=1.176&r2=1.177)
timestamp.c (r1.172 -> r1.173)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/timestamp.c.diff?r1=1.172&r2=1.173)
pgsql/src/include/utils:
datetime.h (r1.64 -> r1.65)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/datetime.h.diff?r1=1.64&r2=1.65)
pgsql/src/interfaces/ecpg/pgtypeslib:
dt.h (r1.35 -> r1.36)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/pgtypeslib/dt.h.diff?r1=1.35&r2=1.36)
dt_common.c (r1.36 -> r1.37)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/interfaces/ecpg/pgtypeslib/dt_common.c.diff?r1=1.36&r2=1.37)