pgsql: Support statement-level ON TRUNCATE triggers.

Log Message:
-----------
Support statement-level ON TRUNCATE triggers. Simon Riggs

Modified Files:
--------------
pgsql/doc/src/sgml:
plperl.sgml (r2.67 -> r2.68)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/plperl.sgml?r1=2.67&r2=2.68)
plpgsql.sgml (r1.124 -> r1.125)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/plpgsql.sgml?r1=1.124&r2=1.125)
plpython.sgml (r1.38 -> r1.39)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/plpython.sgml?r1=1.38&r2=1.39)
pltcl.sgml (r2.47 -> r2.48)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/pltcl.sgml?r1=2.47&r2=2.48)
trigger.sgml (r1.51 -> r1.52)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/trigger.sgml?r1=1.51&r2=1.52)
pgsql/doc/src/sgml/ref:
create_trigger.sgml (r1.47 -> r1.48)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/create_trigger.sgml?r1=1.47&r2=1.48)
truncate.sgml (r1.24 -> r1.25)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/ref/truncate.sgml?r1=1.24&r2=1.25)
pgsql/src/backend/commands:
tablecmds.c (r1.248 -> r1.249)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/tablecmds.c?r1=1.248&r2=1.249)
trigger.c (r1.230 -> r1.231)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/commands/trigger.c?r1=1.230&r2=1.231)
pgsql/src/backend/executor:
execMain.c (r1.304 -> r1.305)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/executor/execMain.c?r1=1.304&r2=1.305)
pgsql/src/backend/parser:
gram.y (r2.610 -> r2.611)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/parser/gram.y?r1=2.610&r2=2.611)
pgsql/src/backend/utils/adt:
ruleutils.c (r1.271 -> r1.272)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/ruleutils.c?r1=1.271&r2=1.272)
pgsql/src/bin/pg_dump:
pg_dump.c (r1.485 -> r1.486)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/bin/pg_dump/pg_dump.c?r1=1.485&r2=1.486)
pgsql/src/include/catalog:
pg_trigger.h (r1.31 -> r1.32)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/catalog/pg_trigger.h?r1=1.31&r2=1.32)
pgsql/src/include/commands:
trigger.h (r1.66 -> r1.67)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/commands/trigger.h?r1=1.66&r2=1.67)
pgsql/src/include/executor:
executor.h (r1.146 -> r1.147)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/executor/executor.h?r1=1.146&r2=1.147)
pgsql/src/include/utils:
rel.h (r1.104 -> r1.105)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/rel.h?r1=1.104&r2=1.105)
pgsql/src/pl/plperl:
plperl.c (r1.138 -> r1.139)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/pl/plperl/plperl.c?r1=1.138&r2=1.139)
pgsql/src/pl/plpgsql/src:
pl_exec.c (r1.206 -> r1.207)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpgsql/src/pl_exec.c?r1=1.206&r2=1.207)
pgsql/src/pl/plpython:
plpython.c (r1.107 -> r1.108)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/pl/plpython/plpython.c?r1=1.107&r2=1.108)
pgsql/src/pl/tcl:
pltcl.c (r1.118 -> r1.119)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/pl/tcl/pltcl.c?r1=1.118&r2=1.119)
pgsql/src/test/regress/expected:
truncate.out (r1.12 -> r1.13)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/expected/truncate.out?r1=1.12&r2=1.13)
pgsql/src/test/regress/sql:
truncate.sql (r1.5 -> r1.6)
(http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/test/regress/sql/truncate.sql?r1=1.5&r2=1.6)