Add MateConfig module

Adapted from:
https://github.com/fcostin/xmonad_and_mate/blob/master/xmonad.hs

~/.xmonad/lib/ documentation:
http://code.google.com/p/xmonad/issues/detail?id=230
Use MateConfig instead of XMonad.Config.Gnome
Make XMonad log hook work with newest version of DBus library

Adapted from:
https://github.com/alexkay/xmonad-log-applet/blob/master/xmonad.hs
Tweak panel applet colors