[xmonad] noModMask

I've got a pair of patches sitting on my hard drive that removes noModMask from xmonad-contrib and bumps the dependency on the X11 library up to the version that includes it. User configs should not need to change -- the module that used to define noModMask now simply imports and re-exports it. Any complaints about pushing those to the public repo? If not, I'll push them in, say, five days. ~d