Etcd

[savorywatt]

I still need to run a cluster test using this on my beefier machine but you can start reviewing the code changes, I've done a lot of testing (using the shell scripts in coordinate) that the registration and cluster startup works, just not full tests yet. Real cluster test some time this week now that I think the code has settled (waiting for a long running backup on my beefier machine to finish before I can test this out).

@tylertreat