Removed cli added support for cobra 

- Added a test file, which matches output of etcdctl commands against regex's 
- exposes a cleaner cobra API
- setDir -> setdir ( consistent with updatedir and mkdir ) 
- hack for exec-watch no longer required 
- peers, no-sync, debug, and output are not persistentFlags and can be attached to any sub-command. 
  etcdctl -o json set /foo bar wil continue to work but so will etcdctl set /foo bar -o json 
- removed third_party folder and replaced with godeps.