[xmonad] darcs patch: Script callbacks for hooks

[Don Stewart]

trevor:
> Hi Everyone,
> 
> I've added the ability to call a script with an argument to direct
> execution.  For example, if you'd like to run a hook on startup that
> does something like manage your dzen2 instance, all you would need to do
> is make sure that:
> 
> > execScriptHook "startup"
> 
> was somewhere in your startup hook definition, and the script
> ~/.xmonad/hooks would be called with a single argument of "startup".
> 

Applied, thanks!

-- Don