[Xmonad] darcs patch: Add simple addTransientUndo finalizer me... (and 1 more)

Here is my proposal for a sufficient extension to Xmonad to allow extension modules to add decoration. I beleive it is sufficient, and more general (it allows capture of arbitrary events, etc). It also adds 13 fewer lines than droundy's patch. Conversely it is not very useful alone, requiring a XMonadContrib.Decoration module to be created. Comments are welcome. Sat Jun 9 12:58:14 PDT 2007 Stefan O'Rear * Add simple addTransientUndo finalizer mechanism for layout modifications (+6 loc) Sat Jun 9 13:40:35 PDT 2007 Stefan O'Rear * Add basic toolkit functionality in the form of an extensible list of event handlers. (+8 loc)