Imports of etcdctlv3 command

PathSynopsis
github.com/coreos/etcd/Godeps/_workspace/src/github.com/codegangsta/cliPackage cli provides a minimal framework for creating and organizing command line Go applications.
github.com/coreos/etcd/etcdctlv3/commandPackage command is a set of libraries for etcd v3 commands.
github.com/coreos/etcd/versionPackage version implements etcd version parsing and contains latest version information.
osPackage os provides a platform-independent interface to operating system functionality.