Update TODO to reflect progress
Update TODO to reflect progress

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