pgsql: Adjust contrib/seg &< and &> operators so that r-tree indexing

Log Message:
-----------
Adjust contrib/seg &< and &> operators so that r-tree indexing logic
works properly for 1-D comparisons.  Fix some other errors such as
bogus commutator specifications.

Modified Files:
--------------
    pgsql/contrib/seg:
        README.seg (r1.4 -> r1.5)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/seg/README.seg.diff?r1=1.4&r2=1.5)
        seg.c (r1.13 -> r1.14)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/seg/seg.c.diff?r1=1.13&r2=1.14)
        seg.sql.in (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/seg/seg.sql.in.diff?r1=1.10&r2=1.11)
    pgsql/contrib/seg/expected:
        seg.out (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/seg/expected/seg.out.diff?r1=1.10&r2=1.11)
        seg_1.out (r1.1 -> r1.2)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/contrib/seg/expected/seg_1.out.diff?r1=1.1&r2=1.2)