pgsql: Make psql \d and \dt consistent for system tables, i.e prevent \d

Log Message:
-----------
Make psql \d and \dt consistent for system tables, i.e prevent \d from
showing system tables, make \dS pattern show system table details, and
have \dtS show system and _user_ tables, to be consistent with other \d*
commands.

Modified Files:
--------------
pgsql/src/bin/psql:
command.c (r1.201 -> r1.202)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/command.c?r1=1.201&r2=1.202)
describe.c (r1.196 -> r1.197)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/describe.c?r1=1.196&r2=1.197)
describe.h (r1.38 -> r1.39)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/describe.h?r1=1.38&r2=1.39)