The start of TweenData.
Evolving the Tween engine. TweenMax string syntax now supported.
repeatAll and loop support added back in.
Planning new vStart cache.
Tidied up code formatting.
Final new tween system is in place (just generateData left to do).
Tweens have been completely rewritten. They're now much more flexible and  efficient than before:
When specifying the ease in `Tween.to` or `Tween.from` you can now use a string instead of the Function. This makes your code less verbose. For example instead of `Phaser.Easing.Sinusoidal.Out` and you can now just use the string "Sine".The string names match those used by TweenMax and includes: "Linear", "Quad", "Cubic", "Quart", "Quint", "Sine", "Expo", "Circ", "Elastic", "Back", "Bounce", "Power0", "Power1", "Power2", "Power3" and "Power4". You can append ".easeIn", ".easeOut" and "easeInOut" variants. All are supported for each ease types.
Tweens now create a TweenData object. The Tween object itself acts like more of a timeline, managing multiple TweenData objects. You can now call `Tween.to` and each call will create a new child tween that is added to the timeline, which are played through in sequence.
Tweens are now bound to the new Time.desiredFps value and update based on the new Game core loop, rather than being bound to time calculations. This means that tweens are now running with the same update logic as physics and the core loop.
Tween.timeScale allows you to scale the duration of a tween (and any child tweens it may have). A value of 1.0 means it should play at the desiredFps rate. A value of 0.5 will run at half the frame rate, 2 at double and so on. You can even tween the timeScale value for interesting effects!
Tween.reverse allows you to instantly reverse an active tween. If the Tween has children then it will smoothly reverse through all child tweens as well.
Tween.repeatAll allows you to control how many times all child tweens will repeat before firing the Tween.onComplete event. You can set the value to -1 to repeat forever.
Tween.loop now controls the looping of all child tweens.
Tween.onRepeat is a new signal that is dispatched whenever a Tween repeats. If a Tween has many child tweens its dispatched once the sequence has repeated.
Tween.onChildComplete is a new signal that is dispatched whenever any child tweens have completed. If a Tween consists of 4 sections you will get 3 onChildComplete events followed by 1 onComplete event as the final tween finishes.
Chained tweens are now more intelligently handled. Because you can easily create child tweens (by simply calling Tween.to multiple times) chained tweens are now used to kick-off longer sequences. You can pass as many Tween objects to `Tween.chain` as you like as they'll all be played in sequence. As one Tween completes it passes on to the next until the entire chain is finished.
Tween.stop has a new `complete` parameter that if set will still fire the onComplete event and start the next chained tween, if there is one.
Tween.delay, Tween.repeat, Tween.yoyo, Tween.easing and Tween.interpolation all have a new `index` parameter. This allows you to target specific child tweens, or if set to -1 it will update all children at once.
Tween.totalDuration reports the total duration of all child tweens in ms.
There are new easing aliases:
* Phaser.Easing.Power0 = Phaser.Easing.Linear.None
* Phaser.Easing.Power1 = Phaser.Easing.Quadratic.Out
* Phaser.Easing.Power2 = Phaser.Easing.Cubic.Out
* Phaser.Easing.Power3 = Phaser.Easing.Quartic.Out
* Phaser.Easing.Power4 = Phaser.Easing.Quintic.Out
Undefined fix #1347