[RFC] vim-patch:7.4.310

```
Problem:    getpos()/setpos() don't include curswant.
Solution:   Add a fifth number when getting/setting the cursor.
```
https://code.google.com/p/vim/source/detail?r=ccac0aa34eeaf46dad4b831461a532fc3fe71096

Docs for neovim/neovim#919