Streaming decoder

[beatgammit]

It would be nice to have a Decoder.Decode like encoding/json for processing streams. I basically want to do:

f, _ := os.Open(filename)
yaml.NewDecoder(f).Decode(&obj)

Instead of:

b, _ := ioutil.ReadFile(filename)
yaml.Unmarshal(b, &obj)

This makes it nicer for decoding yaml documents from io.Readers without having to read everything into a []byte first.

[niemeyer]

This should also consider streams with multiple documents.

[james-lawrence]

+1

[at15]

There is a PR #163 for this issue, but got stuck on CLA

[im-kulikov]

#288 Workaround Encoder/Decoder

[rogpeppe]

Fixed by #301