Changelog Notification - Less intrusive

[msramalho]

The idea is to do one of the following:

1. Add a setting that allows users to disable changelog page opening when chrome updates (there colud be a toggle on the page)
2. insted of displaying the page, display something less intrusive like a tooltip and, if and when the user clicks it, the changelog page is open

[fabiodrg]

I like your suggestions. I am considering using system notifications as the "tooltip". On click, the full changelog options. Notifications on update can be toggled in the settings/options page in a new "General" tab, and on the full changelog itself. I am also considering adding some action when clicking the extension icon in the browser, with an option to open the changelog manually at any time.