Make timezones translatable

Use timezone info in Babel to translate timezones.  Sort
timezones by offset.  Update format to:
    UTC -06:00: United States (Chicago) Time

Thanks amotoki for suggesting to use Babel to handle this!

Not updating environment_version in run_tests.sh because Babel isn't
a new requirement; it's just being made explicit.

Change-Id: I15d39b94d441e9e155870a0593d11e67e68f9bd9
Closes-Bug: #1333927
Merge "Make timezones translatable"