- Redesigned the extension to provide better performance and remove previously noticeable flicker of certain elements when loading data.
- Added persistent user settings to save Clutterfree options.
- Minor redesign of the group cards and their notifications.
- Added options to the /settings/notifications page.

Changes:
- Slight UI redesign to make grouped notifications easier to recognize.
- Logically separated the group header from the first notification of the group (a group will now be made up of one header plus its number of notifications, instead of the header serving as the first notification).
- Pressing the group header item now shows/hides the group items (instead of redirecting to the first notification activity).