I think the last thing that needs to be added to the rest doc is how to post 
messages and files.

Metadata (everything but content) can be done in json.

For msgs, if the message text can be represented as utf8, it can be all posted at 
the same time. Also it could be two posts: metadata post to get a url for the 
message. Then post to the url: message_url/content.

Files however are not the same. We support creation of the metadata using json, but 
I am not sure how we can post the metadata and then set the content separately.
Would we use a multipart/form-data posted to /rest/data/file to include the metadata 
and content?

Comments?