[RFC] vim-patch:7.4.226

Merging vim-patch:7.4.226

Problem:    Cursurline highlighting not redrawn when scrolling. (John
            Marriott)
Solution:   Check for required redraw in two places.

https://code.google.com/p/vim/source/detail?r=b650f2db8f9604124c0ddfb14af0c04bd4ae0580