[Feature] Ecusson Sprites now support unsorted indices

TexturePacker, with certain algorithms, does not generate an
alphabetically sorted sprites indices.

Ecusson now supports that.
[Improvement] Ecusson sprite sends "ended" event better than native

In the native conception of the Corona image sprites, ended events are
thrown at the beginning of the last frame of an animation, not after it,
so it cannot be caught to play another animation for example.

The Ecusson conception handles the loopCount parameter itself and throws
an "ended" event right after the last frame has been played.

Note: This is the same conception as with native Corona Sprites from
SpriteSheets (but now deprecated).