how to scroll up with ngInfiniteScroll for chat pagination

[essi]

Hi,
Please answer this question. I need it very hard.
http://stackoverflow.com/questions/41936420/how-to-scroll-up-with-nginfinitescroll-for-chat-pagination

Thanks

[Thomas Grainger]

dupe of #20 please check for existing issues first.

I don't plan on adding new features. Only bug-fixes.

mdVirtualRepeat can scroll in both directions. Give that directive a go.