If the $last property is calculated from the original collectionLength
on an object and properties starting with $ were filtered out, then $last
is never applied and $middle is applied erroniously.
Closes#1789
I'm reverting changes that were originally done to ngRepeat to fix#933,
because these are now not necessary after the previous changes to keep
ngModel always synced with the DOM.
$position marker doesn't work well in cases when we have just one item
in the list because then the item is both the first and last. To solve
this properly we need to expose individual $first and $middle and $last
flags.
BREAKING CHANGE: $position is not exposed in repeater scopes any more
To update, search for $position and replace it with one of $first,
$middle or $last.
Closes#912
