vim-patch:7.4.659 + test

Problem:    When 'ruler' is set the preferred column is reset. (Issue 339)
Solution:   Don't set curswant when redrawing the status lines.

https://code.google.com/p/vim/source/detail?r=v7-4-659

Helped-by: David Bürgin <676c7473@gmail.com>
Based on #2347 by @pvinis

src/nvim/version.c

@@ -124,7 +124,7 @@ static int included_patches[] = {
   //662,
   //661,
   660,
-  //659,
+  659,
   //658,
   //657,
   //656,