Clean up cottrell algorithm
Clean up cottrell algorithm

rxcomm/mixminion,reezer/mixminion,nmathewson/mixminion,reezer/mixminion,nmathewson/mixminion,crooks/mixminion,mixminion/mixminion,rxcomm/mixminion,Javex/mixminion,nmathewson/mixminion,Javex/mixminion,mixminion/mixminion,Javex/mixminion,crooks/mixminion,crooks/mixminion,reezer/mixminion,reezer/mixminion,rxcomm/mixminion,crooks/mixminion,rxcomm/mixminion,Javex/mixminion,mixminion/mixminion,mixminion/mixminion,nmathewson/mixminion