16.4

• Add support for strict mode.
• Non-enumerable properties of the source object can now be tweened. Values in the destination object must still be enumerable in order for them to be tweened.
• Added an "end" function which is known to randomly fail. Don't use it until we fix that!
• Fixed the timestamp calculation for node.js.
• Removed some redundant start-value copying.
• Removed excess arguments to parseFloat.
• Fixed a possible issue with transpilers and the performance.now polyfill.