AnimComposer: Add Features/Potential issues

To be examined and confirmed:

• tested animation "Standard Walk" from mixamo, the animation does not loop smoothly -> there is a jump at the point when the animation should repeat. (tried deleting the last frame, etc, it did not fix the issue)
  -to test the issue, I set the speed of layer to zero and on key press set speed to one, manually call update, set speed to zero, in order to jump from frame to frame. To my surprise, this produced fluid motion at the point where the animation repeats.

potential new features
-loop modes (cannot run animation exactly once) / listeners
-set animation time directly/set frame directly

PS: I tested if the problem was not in the animation file itself by moving the repeat point into middle (shifted the frames), and the problem was now not present at that point but at the new repeat point.

Start with AnimComposer and reproduce the Standard Walk loop using the described speed-zero, key-press, and manual-update setup. Compare the animation at the repeat boundary, then clarify whether the deliverable is fixing the jump or adding loop modes, listeners, and direct time/frame control. Done requires a confirmed scope and a smooth, repeatable animation loop or explicitly defined feature behavior.