add more fields in sendComment

[tw0517tw]

https://developers.facebook.com/docs/graph-api/reference/v3.1/object/comments#publish

attachment_id, attachment_share_url, attachment_url, source are not supported yet

[chentsulin]

source are not supported yet

[chentsulin]

It would be something like:

client.sendComment(objectId, bufferOrStream)
context.sendComment(bufferOrStream)