adding Juggler entity for animations maintenance

hello,

i was wondering how do you guys maintain animations in js. i tried to find some solution but failed :(
finally, i recalled that in starling (similar actionscript library) there was juggler for nice animation and transition maintenance.

i copied most of implementation from starling. i hope this is useful.
i wonder if can refer them in code somehow (e.g. like @author, which i am actually not) ?

i am going to update this patch some times more, i wish i have some feedback, because i could be implementing something that is already in place in other libraries, maybe you could point me to those.

thank you.