V2.0.0

• Removed dependency on ifvisible and handling the visibility/idle detection in TimeMe itself.
• No existing method calls changed, just new ones introduced. Previous tests still pass as they are.
• Support for callbacks after time period has elapsed.
• Support for callbacks when the user goes inactive or returns.
• Support to pass all configuration in TimeMe.initialize() method.
• Adding support to report statistics via WebSockets. This is optional and disabled by default.