v2_client: read whole response body before close

Client have to read whole response bodies
if they want the advantage of reusing TCP connections.

https://code.google.com/p/go/source/detail?r=d4e1ec84876c0f5611ab86a03826da14b866efb2&name=release-branch.go1.1&path=/src/pkg/net/http/transport.go
server: clear proposal wait in time
etcd: fix transporter leak in test
etcd: add joinThroughFollower test
raft: init lead to none
etcd: reportLead -> getLead
server: refactor client

To be more readable and get rid of false error message.
server: add standby
server: use transporter as raft HTTP handler
server: use status for transporter
server: add TestBecomeStandby
server/v2_client: add func CloseConnections
server: simplify mode transition
etcd: refactor transporter
etcd: transporter->rafthandler
etcd: fix datarace in peer.go
store: fix index data race
etcd: fix mode change race
etcd: move s.ClusterConfig to v2_admin.go
etcd: move s.setClusterConfig to v2_admin.go