[xmonad] Manage hooks

[Ben Boeckel]

On Tue, Dec 20, 2011 at 20:11:14 GMT, Brandon Allbery wrote:
> You *can* have conditional ManageHooks, using ExtensibleState.  I suspect
> it's easier to use something in the same vein as FloatNext, though (but
> that would mean remembering to activate it before creating each window).

I added code which generalizes FloatNext into X.H.ToggleHook. It adds
support for strings in the dynamicLog, updating the dynamic log,
bindings and such. Because they are boolean, dealing with them when they
interact can be tedious (e.g., moving focus back to the current window
whether it shows up under or over the current window).

-- Ben