Animation callbacks should actually be called

[etimberg]

Configuration

The global configuration has two callback functions.

Chart.defaults.global.animation = {
    onProgress: function() {},
    onComplete: function() {},
}

Core Controller

The Core controller attaches different functions from the config to the animation object here

The controller will call onAnimationComplete if the animation duration is 0 milliseconds.

Animation Controller

The animation controller does not fire either onAnimationProgress or onAnimationComplete

Examples

As fixing this, a sample file demonstrating the onAnimationProgress / onAnimationComplete functions should be created.

[etimberg]

Closing as #1775 was merged