Add mappings between CJK Ext B and CNS 11643 plain 7.

Add mappings between CJK Ext B and CNS 11643 plain 7.
(U+8C7C): Use `->subsumptive'.
(U+475E): Use `->denotational' and `->subsumptive' to separate
representative nodes.
(U-00027CEB): Use `->subsumptive' and `->subsumptive'.
(U+4761): Use `->subsumptive'.
(mother of C2-635C): Unify G-CU+8C98.
(C2-635C): Unify CU+8C98.
(U-00027D07): Use `->denotational'.
(r1M-36626): Delete r2M-36626; add `morohashi-daikanwa@rev2' for
M-36628'; map to U-00027D06.
(U+4763): Use `->subsumptive'.
(U+4765): Use `->subsumptive' to separate representative nodes.
(U+4766): Use `->denotational' and `->subsumptive'.
(mother of JX2-792A): Unify G-JU+8C9B and G-CU+8C9B.
(C3-614D): Unify CU+8C9B.