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 do not want to extend the microsyntax... I think there is already a lot going on there and more options will not make it simpler. An alternative would be something based on the `alias`... say create an object named as `alias` with a `$` prepended (and for this object to have the properties)?