[Xmonad] RotView readability patch

[Don Stewart]

emertens:
> Hello,
> 
> I started using RotView recently, but I felt like the code was rather
> difficult to understand at a glance. I wanted to share the changes I
> made in case anyone else felt the same way.
> 
> Other than some minor code changes and library function usage issues, I
> did want to say that RotView does exactly what I wanted.
> 
> (This patch should introduce no new behavior.)

Looks good to me, applied.

-- Don