- qe_isaccent() recognises all combining code points (to be refined)
- add computer generated width table unicode_width.h
- display difference in hex in compare-windows to distinguish
space and nbsp, normal and combined form for accented letters.
- display multiple combining code points in what-cursor-position (C-x =)
- attach combining code points to preceeding space in display_char_bidir
- handle accents specificaaly in flush_fragment
- handle combining code-points in screen backstore via indirection table
this transient table can be inspected via describe-screen
