Exposing AnimatorListener methods in AnimationComposer

[robertoestivill]

Changes implementing the behaviour described in #45 .
Please review and let me know any feedback
Robert

[daimajia]

Hey @robertoestivill , so sorry for my late reply, cause I was too busy on working stuff.

This is a pretty awesome idea for solving ugly overide problem. 👍

Thanks for your working on this. One more request, do you want to be a collaborator of this project if you are avalible ? I believe that you can make this project much better. :-D

[robertoestivill]

@daimajia No problem! we are all pretty busy :)
Like you, I don't currently have a lot of time. However I'm always willing to participate on projects.
I could definitely help on some issues by providing pull requests and so on, but that's about all the commitment I can put into the project.

[daimajia]

@robertoestivill Great! This is open source spirit, though busy, but never forget to share and contribute. 🏆

Let me add you into collaborator list.