browser side: notifications enhancements: - moved sevaral part from Javascript to Python (is hidden, self.enabled) - fixed Notification call (a new was missing) - fixed notification closing: after 5 s, notification is closed (former behaviour was to let the notification visible until manual close) - workaround for Chromium behaviour: notification permission request is not possible on page loading, it need a user interaction. So, if Chromium is detected, Window.onClick is used to request the permission on first click. - for Chromium < 32 (and >= 22) a dialog is shown on loading to indicate how to activate manually notifications - add browser tab highlighting (for pinned tabs), number of unseen notifications is shown in page title