client: add prefix to KeysAPI
client: unexport HTTPKeysAPI
client: MembersAPI.List
Merge pull request #1414 from bcwaldon/client-members-API

Add MembersAPI w/ List method
Merge pull request #1415 from bcwaldon/http-refactor

etcdserver/etcdhttp: break apart http.go
etcdserver/etcdhttp: drop serverHandler from peer handlers
etcdserver/etcdhttp: drop serverHandler from client handlers