Generic updates to transliterations.

- Remove duplicate transliterations for U+0152 and U+0153 from
  C-translit.h.in.
- Change Ö U+00D6 LATIN CAPITAL LETTER O WITH STROKE → O
  (instead of → OE)
- Change ö U+00F6 LATIN SMALL LETTER O WITH STROKE → o
  (instead of → oe)
- Add ₹ U+20B9 INDIAN RUPEE SIGN → INR
- Add ₫ U+20AB DONG SIGN → Dong (in addition to "₫ → Đồng")
- Add many others from
  http://unicode.org/cldr/trac/browser/trunk/common/transforms/Latin-ASCII.xml
- Add some more currency signs suggested by Marko Myllynen
- Add another patch with more characters by Marko Myllynen