Add some mappings between CNS 11643-6 and CJK Ext-B code points.

Add some mappings between CNS 11643-6 and CJK Ext-B code points.
(U+91DE): Use `->subsumptive'.
(U+91DF): Use `->subsumptive'.
(C6-3C64): Unify U-0002893E and H1-C950.
(M-49803): Separate C6-3C62.
(C6-3C62): Unify U-00028940; add `<-unknown' for M-49803.
(U+91E3): Use `->denotational'.
(C6-4577): Map to U-00028944; separate M-40194; use `<-denotational'
to integrate H1-CCB6.
(M-40194): Use `<-denotational' for U-00028944; unify H1-CCB6.
(U+491C): Use `->subsumptive'.
(U+91FE): Likewise.
(U+9204): Likewise.
(U+9206): Use `->subsumptive'.
(U+9220): Use `->subsumptive'.
(U+9268): Likewise.
(U+9269): Use `->denotational'.
(U-00028983): New character; unify M-40344.
(U+92A0): Use `->subsumptive'.
(U+92A4): Use `->subsumptive'.
(U+92A5): Use `->subsumptive'.
(U+92A8): Use `->subsumptive'.