Add sort_array function

This PR adds Hive's ``sort_array`` function that sorts the given array in ascending order according to the natural ordering of its elements (only if the array elements are Comparable).
yep, for small values the ``mapper.readValue()`` call can create integer elements in the resulting list. I hit that case when I did ``ARRAY_SORT(ARRAY [from_unixtime(100), from_unixtime(1), from_unixtime(200)])``