(U+3AD0-var-002): New character; use `<-denotational' for U+3AD0.

(U+3AD0-var-002): New character; use `<-denotational' for U+3AD0.
(U+6611): Add `<-denotational@usage' for BUCS+6611; apply new
conventions for glyph granularity.
(U+6668): Add `<-denotational@usage' for BUCS+6668; apply new
conventions for glyph granularity.
(U+3AF3): Add `ideographic-structure'; add `sound@ja/on'.
(AJ1-15424): Unify MJ001607 and KOSEKI-157140; add `<-formed' and
`<-same' for UU+6668.
(U+66DF): Apply new conventions for glyph granularity.
(BUCS+6611): New abstract node.
(BUCS+6668): New abstract node; unify A2-DJT-04554.