Switched Set to Create
Make interval a constant on proxy/config/etcd

Allow future testing of intervals
Remove long sleeps from proxy tests
Validate on replicas being non-negative
Merge pull request #772 from derekwaynecarr/stop_negative_values

Validate on replicas being non-negative
Merge pull request #740 from brendandburns/sync

Switched Set to Create in etcd tools
Merge pull request #773 from smarterclayton/speed_up_proxy_tests

Remove 8 seconds of unnecessary sleeps from proxy tests