Add an example and more comments to the documentation, and make some
small code tweaks (more type signatures and a couple variable renames)
to aid readability.
I was naively passing the workspace to runLayout without filtering out
floating windows from its stack, like XMonad.Operations.windows does.
The fact that 'windows' does this filtering explains how layouts like
those in LimitWindows continue to behave correctly in the presence of
floating windows.
This fixes some incorrect behavior where the presence of a floating
windows caused visible windows (other than the focused one) to be
included in the surfaceRing.
This module provides a pure function, 'rotateSome', as well as a pair of
X actions that use it to rotate unshown windows through the focused
stack position while leaving other windows in place. I find this useful
in combination with layouts such as LimitWindows, which determine window
visibility based on stack position.
