- Add Hanyo-Denshi/IA code points.

- Add Hanyo-Denshi/IA code points.
- Add `=decomposition@hanyo-denshi' for some abstract glyph-forms of
  Hanyo-Denshi/IA.
- Add some MJ code points corresponding to Hanyo-Denshi IVSes.
(U+5428): Add `<-denotational@usage' for BUCS+5678 and A2-DJT-01192.
(JU+5428): Unify DJT-01192.
(U+356F): Add `<-denotational@usage' for BUCS+5436; apply new
conventions for glyph granularity.
(U+5436): Likewise.
(U+554C): Add `<-denotational@usage' for BUCS+554C.
(U+35D6): Add `<-denotational@usage' for A2-DJT-01376.
(UU+35D6): Unify DJT-01443.
(U-00020E55): Add `sound@ja/on/{kan|go}'; apply new conventions for
glyph granularity.
(U+5605): Add `<-denotational@usage' for BUCS+6168; apply new
conventions for glyph granularity.
(U+5612): Add `<-denotational@usage' for A2-DJT-01475.
(JU+5612): Unify DJT-01475.
(U+35F4): Apply new conventions for glyph granularity.
(U+5644): Likewise.
(U+565A): Likewise.
(U+5678): Add `<-denotational@usage' for BUCS+5678 and A2-DJT-01537.
(JU+5678): Unify DJT-01537.
(U+56A8): Apply new conventions for glyph granularity.
(U-000210E1): Use `->denotational' and `->subsumptive'.
(BUCS+5678): New abstract node.
(BUCS+5436): New abstract node; unify A2-DJT-01209.
(BUCS+554C): New abstract node.
(A2-DJT-01376): New abstract node.
(A2-DJT-01475): New abstract node.
(A2-DJT-01192): New abstract node; use `<-denotational' for BUCS+5678.
(A2-DJT-01537): New abstract node; use `<-denotational' for BUCS+5678.