Fix window positions.
Graph and diff windows were swapped if user set `splitbelow` to 1:
    :set splitbelow    :set nosplitbelow
       +---+---+           +---+---+
       | D |   |           | G |   |
       +---+ S |           +---+ S |
       | G |   |           | D |   |
       +---+---+           +---+---+
     D - diff,  G - graph,  S - source
This commit fixes this -- now diff is displayed below graph regardless of
`splitbelow` setting.
    
        | author | 
        Maciej Konieczny <hello@narf.pl> | 
    
    
        | date | 
        Sun, 22 May 2011 21:54:55 +0200 | 
    
    
        | parents | 
        2b3d5ee5c4a4  | 
    
    
        | children | 
        (none) | 
    
set nocompatible
set runtimepath=vim_test
filetype plugin on
nnoremap q :qa!<cr>
color desert