[Vimdiff] Use vimdiff to merge code

Jump to the file which want merge with other.
:diffget will get the line from the other panel.
:diffput will put the line to the other panel.

:diffupdate will update current diff.

:qa close all
:wqa  save all tabe and close all

Reference:
1. Using Vim as a Merge Program for Mercurial
2. How do I close all open tabs in VIM at once?