Pacman module

Sorry for the late pull-request. It should be done, there are a few things I had to change (I was reading the man pages for pacman). I've added my contact info, ansible version (0.0.9), and modified the code to use "pacman -Q" which will only match the exact name instead of "pacman -Qs" which will match any package with that part of the name. Also its using "pacman -Qu" which will (based on return codes) tell me if the package is the latest or not. I've used "name" with the alias "pkg". State has "latest", "installed", "absent" which "latest" will trigger a "pacman -Syy" (package db update).