Drag & dropping directories into davros creates empty regular files

[zenhack]

I just discovered that if you try to add a directory to Davros by dragging & dropping it from the file manager, Davros creates an empty, regular file by the same name, instead of a directory. I can reproduce this as of 0.31.1

[zenhack]

It looks like this is an issue with the upstream file upload library that davros is using: adopted-ember-addons/ember-file-upload#2