Data endpoint requires autometa=true

[nguyer]

Right now, if someone attempts to upload a file to the /namespaces/{namespaceId}/data endpoint, and only sets the file field, the request will fail with the following response:

HTTP 500 Internal Server Error

{
    "error": "FF10116: Database insert failed: NOT NULL constraint failed: data.value"
}

As a workaround it is possible to get this to work by adding another field to the form called autometa and setting its value to be true. This upload should work without needing to set this field though.

[peterbroadhurst]

You can also set metadata to be any valid JSON

[peterbroadhurst]

Fixed in #207 to allow a null value