Gmail may soon look nothing like the Gmail we all know so well. Google has invited a select group of users to test a completely new interface for the webmail client, according to Geek.com, which appears to be part of the trial. The test version of Gmail — which may never see an official release — dispenses with design elements that have been present from the very early days of the email service. Most notably, the unwieldily sidebar has been replaced with a slide-in pane. Buttons like “compose” have been moved to the bottom right corner, and it looks like there’s another new feature down there: reminders. Just like on Android, you should be able to tell Google to let you know about a date in the future or to respond to a certain email….