Bump version (and xmonad dependency) to 0.12
Bump version (and xmonad dependency) to 0.12

This makes a breakage due to missing patches in core a bit more obvious.
Previously you would have a build failure regarding some missing identifiers
(def re-exported by XMonad from Data.Default), while after applying this patch
it will be clear that xmonad-core needs to be updated.


MP2E/XMonadContrib,MP2E/XMonadContrib