raft: protobuf messageType
Merge pull request #1293 from unihorn/160

raft: protobuf messageType
etcdserver: change machines endpoint to members
Merge pull request #1290 from coreos/member_endpoint

etcdserver: change machines endpoint to members
etcdserver: clean NewServer
etcdserver: add shouldDiscover
etcdserver: add s.apply
etcdserver: Id -> ID
etcdserver: fix typo
Merge pull request #1288 from coreos/cleanup

etcdserver: clean NewServer
etcdhttp: add PUT and DELETE on /v2/admin/members/