Progress bars when you have a huge number of simultaneous transforms

[gordonwatts]

When submitted a request that contains 100 or 200 datasets, you get the proper number of scroll bars. However, that is untenable on the command line and in a notebook.

This issue is to come up with a solution (combined progress bar? etc.) and track its implementation.

[ponyisi]

Partial solution in #556 (does not include an app option, but the API support is there).