Update development references (darcs, code.google.com, etc.)

* All references to darcs have been updated to git

  * Most Google Code references have been changed to GitHub

  * References to specific issues at code.google.com have been left
    alone

  * Updated the GenerateManpage.hs to work with the latest version of
    pandoc

XMonad/Doc.hs

@@ -49,9 +49,9 @@ import XMonad.Doc.Developing ()
 xmonad is a tiling window manager for X. The xmonad-contrib library
 collects third party tiling algorithms, hooks, configurations,
 scripts, and other extensions to xmonad.  The source for this library
-is available from <http://code.haskell.org/XMonadContrib> via darcs:
+is available from <https://github.com/xmonad/xmonad-contrib> via git:
 
-> darcs get http://code.haskell.org/XMonadContrib
+> git clone https://github.com/xmonad/xmonad-contrib.git
 
 Each stable release of xmonad is accompanied by a stable release of
 the contrib library, which you should use if (and only if) you're

XMonad/Doc/Extending.hs

@@ -102,7 +102,7 @@ For more information about any particular module, just click on its
 name to view its Haddock documentation; each module should come with
 extensive documentation.  If you find a module that could be better
 documented, or has incorrect documentation, please report it as a bug
-(<http://code.google.com/p/xmonad/issues/list>)!
+(<https://github.com/xmonad/xmonad/issues>)!
 
 -}