A::slice() should work with negative indices

[meszaros-lajos-gyorgy]

The internally used array_slice has this feature and seems to work correctly:

<?php

$data = [1, 2, 3, 4, 5];

echo '<pre>';

print_r(array_slice($data, 0, -2));

http://phptester.net/ displays the following as output for php 7.0 and above:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
)