- New etcd client

- Experimental v3 API and new storage demo
- Active cluster health checking
- Improved documentation
- v2 API change
- Default GOMAXPROCS changes with Go 1.5
- Support Dedicated WAL Directory
- Introduce flag `--endpoint` in etcdctl

- when invalid TLS files are provided etcd logs a helpful error messa…

…ge and shuts down cleanly

Main changes:

- add the authentication feature to the v2 API, providing users, roles and basic authentication
- provide more stable transportation between etcd members
- introduce functional testing framework
- provide leveled logging
- introduce metrics feature

Main changes:

- add the authentication feature to the v2 API, providing users, roles and basic authentication
- provide more stable transportation between etcd members
- introduce functional testing framework
- provide leveled logging
- introduce metrics feature