pgsql: Create a FETCH_COUNT parameter that causes psql to execute

Log Message:
-----------
Create a FETCH_COUNT parameter that causes psql to execute SELECT-like
queries via a cursor, fetching a limited number of rows at a time and
therefore not risking exhausting memory.  A disadvantage of the scheme
is that 'aligned' output mode will align each group of rows independently
leading to odd-looking output, but all the other output formats work
reasonably well.  Chris Mair, with some additional hacking by moi.

Modified Files:
--------------
    pgsql/doc/src/sgml/ref:
        psql-ref.sgml (r1.166 -> r1.167)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/psql-ref.sgml.diff?r1=1.166&r2=1.167)
    pgsql/src/bin/psql:
        common.c (r1.126 -> r1.127)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/common.c.diff?r1=1.126&r2=1.127)
        print.c (r1.88 -> r1.89)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/print.c.diff?r1=1.88&r2=1.89)
        print.h (r1.31 -> r1.32)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/print.h.diff?r1=1.31&r2=1.32)
        settings.h (r1.29 -> r1.30)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/settings.h.diff?r1=1.29&r2=1.30)
        startup.c (r1.136 -> r1.137)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/bin/psql/startup.c.diff?r1=1.136&r2=1.137)