pgsql: TG_table_name and TG_table_schema for plpgsql, plus docs and

Log Message:
-----------

TG_table_name and TG_table_schema for plpgsql, plus docs and regression.

Modified Files:
--------------
    pgsql/doc/src/sgml:
        plpgsql.sgml (r1.88 -> r1.89)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/plpgsql.sgml.diff?r1=1.88&r2=1.89)
    pgsql/src/pl/plpgsql/src:
        pl_comp.c (r1.101 -> r1.102)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_comp.c.diff?r1=1.101&r2=1.102)
        pl_exec.c (r1.164 -> r1.165)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_exec.c.diff?r1=1.164&r2=1.165)
        plpgsql.h (r1.69 -> r1.70)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/plpgsql.h.diff?r1=1.69&r2=1.70)
    pgsql/src/test/regress/expected:
        triggers.out (r1.20 -> r1.21)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/triggers.out.diff?r1=1.20&r2=1.21)
    pgsql/src/test/regress/sql:
        triggers.sql (r1.10 -> r1.11)
        (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/triggers.sql.diff?r1=1.10&r2=1.11)