Changes

With the transition to the Rapid Release development model, the frequency in which we interrupt a user's workflow will be increasingly more common. With goals to offer a secure, feature-rich, and fun browsing experience, we want to ensure everyone is on the latest version of Firefox. To achieve this goal, this particular feature will breakdown the necessary pieces to deliver a silent update experience.

<b>1) Move bulk of update to background before shut down and remove update UI from browser start-up. ([https://wiki.mozilla.org/Silent_Update_updater feature page]):</b>