Fix no_split and no_buffer  and keep cursor position when using replace_all

These commits seem to fix two issues:

 i) recent renaming of Unite's [no_split](https://github.com/Shougo/unite.vim/commit/4ef321ba2c53451dfab8ec548917c07b81a76d5e) and [no_buffer](https://github.com/Shougo/unite.vim/commit/d2613e981879ef2948fc3460413e27679ff8cdd8). 
ii) Issue [#7](https://github.com/kopischke/unite-spell-suggest/issues/7)

Please review both changes (especially the second one because I'm not quite sure whether the proposed fix is correct despite it seems to work).