transport: no need to set RootCAs in TLSInfo.ServerConfig
etcdserver: pass http client into Sender
etcd: manually construct HTTP client for peer communication
transport: add TLSInfo.ClientConfig
transport: build TLS config in NewTransport
etcd: wire up peer TLS flags
etcdserver: Peers.Pick returns just an addr
etcdserver: pass scheme into send
etcdserver: determine scheme based on TLSClientConfig
etcd: use TLS in proxy transport
etcdserver: add Peers.Addrs
proxy: pass addrs and scheme into newDirector
proxy: determine scheme based on TLSClientConfig
transport: spot-check NewTransport
transport: test TLSInfo.Empty()
transport: exercise TLSInfo.ClientConfig & ServerConfig
Merge pull request #1142 from bcwaldon/TLS

TLS: peer server/transport and proxy transport