Inheritance overhaul by Chris Bitmead <chris@bitmead.com>

doc/FAQ_DEV

doc/src/sgml/advanced.sgml

doc/src/sgml/catalogs.sgml

doc/src/sgml/inherit.sgml

doc/src/sgml/ref/alter_table.sgml

doc/src/sgml/ref/create_table.sgml

doc/src/sgml/ref/delete.sgml

doc/src/sgml/ref/select.sgml

doc/src/sgml/ref/set.sgml

doc/src/sgml/ref/update.sgml

doc/src/sgml/syntax.sgml

src/backend/commands/creatinh.c

src/backend/commands/variable.c

src/backend/executor/nodeAppend.c

src/backend/nodes/list.c

src/backend/optimizer/plan/planner.c

src/backend/optimizer/util/plancat.c

src/backend/parser/analyze.c

src/backend/parser/gram.y

src/backend/parser/keywords.c