[RFC]vim-patch:7.4.309

updated for version 7.4.309
Problem:    When increasing the size of the lower window, the upper window
            jumps back to the top. (Ron Aaron)
Solution:   Change setting the topline. (Nobuhiro Takasaki)

https://code.google.com/p/vim/source/detail?r=88a6e9f33822d33b6c32db578750c6c178c63f50
Careful: these patches often fix things that they broke a few commits earlier. So when integrating a patch, it must be applied on top of previous patches that you may have PRs open for (but we didn't merge yet).

LIn this case, line 4563 was changed by a previous patch, but this patch was supposed to *change* it back to:

    } else if (sline > 0) {

That change isn't in this PR so it won't get applied to the line which is now broken by a previous patch :)