Fix stream when using socket

As discussed in #34, we should call net.Dial for unix sockets.
I forget the stream function when I created by pull request.
I need to add more tests :(
Merge branch 'master' into fix-stream-unix-socket
Use a real unix socket server to test stream
Merge branch 'fix-stream-unix-socket' of github.com:gemnasium/go-dockerclient
test: replace /tmp with os.TempDir()
testing/server: reformatting code