Add a console progress bar

Summary:
Ref T988. This is pretty fluff, but we have a few processes that do long-running processing and either don't report progress or do something relatively un-useful like printing a lot of dots.

Provide a progress bar with reasonable behaviors (notably: awareness of TTYs, of --trace, of console widths, and of exceptions).

Test Plan: Ran progress_bar.php script under all the special conditions it notes.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran, chad

Maniphest Tasks: T988

Differential Revision: https://secure.phabricator.com/D6813