ZIP bulk download unecessary multi-level zipping

There is something fondamentally wrong with the bulk download operation (Blob.BulkDownload). Each level of subfolder is zipped. A subfolder is zipped, then included in the zip of its parent folder and so on. 

This is problematic for several reasons:

• it's a complete waste of server resources
• the resulting zip file is virtually unusable as a end user needs to manually unzip all the subfolder levels

How to reproduce:

• in webui, create a hierachy of folders, subfolders and files.
• bulk download the top folder