Array mega-patch.

doc/src/sgml/array.sgml

doc/src/sgml/func.sgml

src/backend/catalog/pg_aggregate.c

src/backend/commands/aggregatecmds.c

src/backend/executor/execQual.c

src/backend/executor/nodeAgg.c

src/backend/executor/nodeSubplan.c

src/backend/nodes/copyfuncs.c

src/backend/nodes/equalfuncs.c

src/backend/nodes/outfuncs.c

src/backend/nodes/readfuncs.c

src/backend/optimizer/plan/subselect.c

src/backend/optimizer/util/clauses.c

src/backend/parser/gram.y

src/backend/parser/parse_coerce.c

src/backend/parser/parse_expr.c

src/backend/parser/parse_func.c

src/backend/parser/parse_oper.c

src/backend/utils/adt/acl.c

src/backend/utils/adt/array_userfuncs.c