Type table feature

doc/src/sgml/information_schema.sgml

doc/src/sgml/ref/create_table.sgml

src/backend/bootstrap/bootparse.y

src/backend/catalog/heap.c

src/backend/catalog/information_schema.sql

src/backend/catalog/toasting.c

src/backend/commands/cluster.c

src/backend/commands/tablecmds.c

src/backend/executor/execMain.c

src/backend/nodes/copyfuncs.c

src/backend/nodes/equalfuncs.c

src/backend/nodes/outfuncs.c

src/backend/parser/gram.y

src/backend/parser/parse_utilcmd.c

src/bin/pg_dump/pg_dump.c

src/bin/pg_dump/pg_dump.h

src/bin/psql/describe.c

src/include/catalog/catversion.h

src/include/catalog/heap.h

src/include/catalog/pg_class.h