Download/Upload Progress

[sujaygarlanka]

Goals ⚽

• Add ability to view progress for uploads and downloads

Implementation Details 🚧

• Add observer to progress object on a task

Testing Details 🔍

• Manual Testing

[boxcla]

Verified that @sujaygarlanka has signed the CLA. Thanks for the pull request!

[PJSimon]

Do you need to change the last lines of Gemfile.lock from:
BUNDLED WITH 2.0.1
to
BUNDLED WITH 2.1.0
This is a change you had made in the past.

[sujaygarlanka]

That change was made when I recompiled the Gemfile in the previous PR. However, since nothing changed in the Gemfile when I compiled it last, I didn't compile it this time. However, one of the travis tests are not passing now, so I'll add in the change.