Merge pull request #109 from coreos/upstream

Update
Use os.File.Sync.
Merge pull request #111 from mattn/windows

Build on windows
Merge pull request #110 from coreos/conf

Conf
Minor refactor of AddPeer/RemovePeer.
Merge pull request #112 from goraft/minor-refactor-add-remove-peer

Minor refactor of AddPeer/RemovePeer.
Use github.com/coreos/go-raft import path

Rebase this patch on top of the upstream branch for keeping the coreos
go-raft paths. This is needed for the recently added protobuf
sub-package.

    git pull --rebase origin upstream