Allow passing a custom test function to table.column(colIdx).search()

This allows table-specific filtering with a custom "test" function. The example at https://next.datatables.net/plug-ins/filtering/row-based/range_numbers seems to perform global filtering that applies to all the tables.

Filter by range (similar to the example at https://next.datatables.net/examples/api/multi_filter.html):

table.column(colIdx).search(function (value){
    value = +value;
    return min <= value && value <= max;
}).draw();