Added a readme for libpaxos
Added a readme for libpaxos

columbia/xtern,hemingcui/xtern_with_paxos,hemingcui/xtern_with_paxos,columbia/xtern,hemingcui/xtern_with_paxos,columbia/xtern,hemingcui/xtern_with_paxos,hemingcui/xtern_with_paxos,columbia/xtern,columbia/xtern,columbia/xtern