Bugfix? requestAnimationFrame being called forever

[amyleesalesforce]

Maybe a fix?

It seems that requestAnimationFrame is called forever because it's inside the oninterval() callback. But by moving it into the while() loop the requestAnimationFrame() will only called back if there are still use tags to replace.

[fregante]

I think #86 fixed this

[jonathantneal]

@amyleesalesforce, thanks for your optimization. So, I am calling requestAnimationFrame forever because I am using it to listen to changes in the DOM that may include new <use> tags. This is obviously not an ideal way to listen to changes in the DOM, since we have awesome things like Mutation Observers that might work better, as long as we use fallbacks down to IE9 or IE8.

I’m really hoping someone (you? or maybe #33) could move me in that direction.