change the default ediff-split-window-function to split-window-horizontally

[Dan Nicolaescu]

Can we change the default ediff-split-window-function to
split-window-horizontally ? 

All the GUI diff applications that I know off: xxdiff, meld, kdiff,
kompare display the 2 files side by side. 
So it seems that now users expect diff applications to display the
files side by side.

The reason to change is not only to blindly follow other applications,
but the side-by-side display is superior. 
It is easier for the eye to follow differences when they are side by
side (even the expression is: "side-by-side comparison" not "one on
top of the other comparison").

The current default might be familiar to people used to look at
diff(1) output, but that is not the majority of users.

Opinions?

Thanks
                --dan