feat: onAnimLoop, onAnimEnd and onAnimStop

[lajbel]

Please describe what issue(s) this PR fixes.

This feature differentiates 3 kinds of moments in an animation end:

• onEnd:
  • Last frame is reached
• onStop:
  • Last frame is reached
  • Is changed by using obj.play()
  • Is stopped by using obj.stop()
• onLoop:
  • Normally, when last frame is reached and animation is looped
  • In case of pingpong, when last or first frame is reached and animation is looped

Summary

• Closes bug: onEnd/onAnimEnd doesn't run when an animation in loop ends #819
• Changeloged

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/kaplayjs/kaplay@822

commit: e2bf7e0