Stacked progress bar is incompatible with aria-valuenow=0

Created by: chrisirhc

When using stacked progress bars, the value 0 is not usable with the aria-valuenow attribute.

See: http://plnkr.co/edit/MqKBgSEWHidDY6lNFWwG?p=preview

This is due to the min-width for the [aria-valuenow=0] pushing the 100% bar element to the next line.

Discovered while testing https://github.com/angular-ui/bootstrap/issues/2511 .