Add glyph-images of HNG-KHM.

Add glyph-images of HNG-KHM.
(HNG-KHM0121-0): New character; `<-denotational' for BUCS+8A2D; add
`<-formed' for U+8A2D.
(HNG-KHM0528-0): New character; `<-denotational' for BUCS+8A63; add
`<-formed' for U+8A63.
(U+8B58): Separate UU+8B58.
(HNG-KHM0523-0): New character; `<-denotational' for U+8B58.
(U+8B70): Separate UU+8B70.
(UU+8B70): Add `=>ucs@iwds-1'.
(HNG-KHM0529-0): Add `<-denotational' for U+8B70.
(U+8B77-itaiji-002): New character to subsume HNG-KHI0172-0 and
HNG-KHM0531-0; add `<-denotational' for U+8B77; add `<-formed' for
U+8B77.