Add notifications
An improvement to the game would be to be able to add opt-in notifications with the following options:
- Disable: Notifications are not displayed (as now)
- Out of focus: Notifications are displayed when the game window is not in focus
- Always: Notifications are always displayed
The notifications would mainly alert on a new opponent's movement (describing the movement) and could even show a button to pause the game in the limited time mode, etc.