feat(ngRepeat): expose the iterating properties over the alias

Expose the properties `$index`, `$first`, `$middle`, `$last`, `$odd` and `$even` as part of the alias

Closes #9582
I'm kinda torn on this --- I know I said it's better than the other thing, but I'm not sure... it sucks this way too =\

I think I need someone else to weigh in on which way would be better. I don't like potentially shadowing object keys, and I don't like the slight impact of crawling up the prototype chain. But maybe it's better than this