standardized format for errors

[sknebel]

It'd be nice to have some standard for error messages, to be able to show them to the user in a nicer way than a plain HTTP transcript. Maybe just something along the lines of "use json, "message":"your error text here" for starters?

[aaronpk]

Probably best to use the same format as Micropub: https://www.w3.org/TR/micropub/#error-response

[sebsel]

I was about to file this one, so just a 1+. I'm going to use the Micropub one's for now, seems like a good choice.

[dshanske]

Aperture uses this format.