DVWebloader doesn't yet support file/total size limits on datasets

[qqmyers]

If limits are enabled, Dataverse will return 400 errors when an upload would violate them. DVWebloader doesn't handle those at present.

There is also a new http://localhost:8080/api/datasets/$dataset-id/uploadlimits api call that will show the remaining number of files/bytes allowed during upload - these could be displayed and enforced when DVWebloader is selecting files for uploads.