Copy store.Response into go-etcd.
Merge pull request #40 from benbjohnson/decouple-response

Copy store.Response into go-etcd.
Merge branch 'master' of github.com:coreos/go-etcd into 0.2

Conflicts:
	etcd/delete.go
	etcd/get.go
	etcd/set.go
	etcd/testAndSet.go