$position in repeat directive can't be both first and last at the same time

[maxmart]

Currently the $position property inside the repeat directive is either 'first', 'middle' or 'last'.
But if the list only has one item, the $position is set to 'first' by angular, even though it is actually both the first and last item.

Since this subtlety can't (reasonably) be represented by a single variable, something else is required. One way to solve it would be to have three boolean properties, $first, $middle and $last instead.