(char-db-coded-charset-priority-list): Use `=daikanwa' and

(char-db-coded-charset-priority-list): Use `=daikanwa' and
`=daikanwa@rev1' instead of `ideograph-daikanwa' and
`ideograph-daikanwa-2'; add `=daikanwa@rev2'.
(char-db-insert-char-spec): Modify for `insert-char-attributes' to
specify optional argument `for-sub-node'.
(char-db-insert-alist): Likewise.
(char-db-insert-relation-feature): Likewise.
(insert-char-attributes): Add optional argument `for-sub-node'; insert
`<-subsumptive' feature if `for-sub-node' is nil.