pgsql: Add new columns for tuple statistics on a database level to

Log Message:
-----------
Add new columns for tuple statistics on a database level to
pg_stat_database.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        monitoring.sgml (r1.46 -> r1.47)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/monitoring.sgml.diff?r1=1.46&r2=1.47)
    pgsql/src/backend/catalog:
        system_views.sql (r1.35 -> r1.36)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/catalog/system_views.sql.diff?r1=1.35&r2=1.36)
    pgsql/src/backend/postmaster:
        pgstat.c (r1.148 -> r1.149)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/pgstat.c.diff?r1=1.148&r2=1.149)
    pgsql/src/backend/utils/adt:
        pgstatfuncs.c (r1.39 -> r1.40)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/pgstatfuncs.c.diff?r1=1.39&r2=1.40)
    pgsql/src/include:
        pgstat.h (r1.54 -> r1.55)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/pgstat.h.diff?r1=1.54&r2=1.55)
    pgsql/src/include/catalog:
        catversion.h (r1.389 -> r1.390)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/catversion.h.diff?r1=1.389&r2=1.390)
        pg_proc.h (r1.447 -> r1.448)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_proc.h.diff?r1=1.447&r2=1.448)
    pgsql/src/test/regress/expected:
        rules.out (r1.125 -> r1.126)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/rules.out.diff?r1=1.125&r2=1.126)