[WIP] vim-patch:7.4.324

Problem:   In Ex mode, cyrillic characters are not handled. (Stas Malavin)
Solution:   Support multi-byte characters in Ex mode. (Yukihiro Nakadaira)

https://code.google.com/p/vim/source/detail?r=c476e0ac8b406693c3877baffa0e97ff25e59b06

- I have changed one prefix ++ operator to postfix.
- I'm not sure about the formatting of the ifdefs, maybe some adjustments will be needed there
- Does anyone know how to test this patch? Maybe there is someone on the Neovim team who uses Cyrillic characters.
@atwupack, yes the `ga_grow(&line_ga,1);` before line 1843 should be enough to make sure we can write a byte at the end.