pull suppressWhen logic into main WithUrgencyHook handler
pull suppressWhen logic into main WithUrgencyHook handler

In order for this to work, I added a new UrgencyHook method to communicate the
SuppressWhen value. I'm not sure if this is actually better than just providing
a convenience function, but it's an easy switch.

xmonad/xmonad-contrib,ohlus/xmonad-contrib,xmonad/xmonad-contrib,pjones/xmonad-test,ohlus/xmonad-contrib,f1u77y/xmonad-contrib,mathstuf/xmonad-contrib,0/xmonad-contrib,CaptainPatate/xmonad-contrib,CaptainPatate/xmonad-contrib,ohlus/xmonad-contrib,f1u77y/xmonad-contrib,mathstuf/xmonad-contrib,0/xmonad-contrib,mathstuf/xmonad-contrib,CaptainPatate/xmonad-contrib,0/xmonad-contrib