Auto-update, new revamped UI & improved logout

Improvements for all users:

• Updates will now be detected automatically when starting Cozy Drive.
  When an update is available, a splash screen will ask you to wait while
  downloading (including the download progress on Windows only) and the app
  will restart automatically. When no update is available, the app will start
  as usual. Since the update check is quite fast, we decided to display a
  splash screen only during download, not while checking. In case of network
  issues, the app may take more time to start than usual, but it should still
  work.
• New revamped UI: the dashboard window was replaced with a popover showing
  up next to the (new) system tray icon. The synchronization status on top of
  the popover should give you more indications about what is actually occurring
  in the background. Navigation was simplified and moved to the top of the
  popover and the help form now shows up in its own separate window.
• Disconnecting the device from the Cozy or the app should work as expected
  now. Also since most people encountering issues were trying to reconfigure
  their device, we made sure logs were not deleted anymore in the process.

See known issues.

Happy syncing!