Update loading-bar.js - #119

Hmm, almost, but this doesn't account for the scenario when one XHR relies on the response from another.

In this scenario, a single XHR request goes out, the loading bar increments a bit, and when it comes back, the loading bar goes to 100%, but at the same time, another XHR request goes out using data it received from the first. In this case, the loading bar waits at 100% until receiving the second XHR response, so the experience is actually worse than the loading bar jumping backwards as it makes the UI feel like it froze.

This could probably be resolved by not setting the progress bar's width to 100% until the $timeout here completes.

Closing due to inactivity.