pgsql: Rename contains/contained-by operators to @> and <@, per

Log Message:
-----------
Rename contains/contained-by operators to @> and <@, per discussion that
agreed these symbols are less easily confused.  I made new pg_operator
entries (with new OIDs) for the old names, so as to provide backward
compatibility while making it pretty easy to remove the old names in
some future release cycle.  This commit only touches the core datatypes,
contrib will be fixed separately.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        func.sgml (r1.334 -> r1.335)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/func.sgml.diff?r1=1.334&r2=1.335)
        indices.sgml (r1.59 -> r1.60)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/indices.sgml.diff?r1=1.59&r2=1.60)
    pgsql/src/backend/access/gin:
        README (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/gin/README.diff?r1=1.1&r2=1.2)
    pgsql/src/backend/access/gist:
        gistproc.c (r1.7 -> r1.8)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/gist/gistproc.c.diff?r1=1.7&r2=1.8)
    pgsql/src/include/access:
        gist.h (r1.54 -> r1.55)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/access/gist.h.diff?r1=1.54&r2=1.55)
    pgsql/src/include/catalog:
        catversion.h (r1.354 -> r1.355)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h.diff?r1=1.354&r2=1.355)
        pg_amop.h (r1.73 -> r1.74)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_amop.h.diff?r1=1.73&r2=1.74)
        pg_operator.h (r1.144 -> r1.145)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_operator.h.diff?r1=1.144&r2=1.145)
        pg_proc.h (r1.422 -> r1.423)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_proc.h.diff?r1=1.422&r2=1.423)
    pgsql/src/test/regress/expected:
        arrays.out (r1.30 -> r1.31)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/arrays.out.diff?r1=1.30&r2=1.31)
        box.out (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/box.out.diff?r1=1.10&r2=1.11)
        create_index.out (r1.21 -> r1.22)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/create_index.out.diff?r1=1.21&r2=1.22)
        geometry.out (r1.22 -> r1.23)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/geometry.out.diff?r1=1.22&r2=1.23)
        geometry_1.out (r1.7 -> r1.8)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/geometry_1.out.diff?r1=1.7&r2=1.8)
        geometry_2.out (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/geometry_2.out.diff?r1=1.4&r2=1.5)
        opr_sanity.out (r1.66 -> r1.67)

(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/opr_sanity.out.diff?r1=1.66&r2=1.67)
        point.out (r1.14 -> r1.15)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/point.out.diff?r1=1.14&r2=1.15)
        polygon.out (r1.12 -> r1.13)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/polygon.out.diff?r1=1.12&r2=1.13)
    pgsql/src/test/regress/sql:
        arrays.sql (r1.23 -> r1.24)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/arrays.sql.diff?r1=1.23&r2=1.24)
        box.sql (r1.6 -> r1.7)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/box.sql.diff?r1=1.6&r2=1.7)
        create_index.sql (r1.20 -> r1.21)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/create_index.sql.diff?r1=1.20&r2=1.21)
        geometry.sql (r1.8 -> r1.9)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/geometry.sql.diff?r1=1.8&r2=1.9)
        opr_sanity.sql (r1.52 -> r1.53)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/opr_sanity.sql.diff?r1=1.52&r2=1.53)
        point.sql (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/point.sql.diff?r1=1.10&r2=1.11)
        polygon.sql (r1.8 -> r1.9)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/polygon.sql.diff?r1=1.8&r2=1.9)