Description:
------------
Currently, only object and array arguments of a function can be hinted. However, if you can't hint non-class/non-array argument, you have to leave argument unhinted, which allows passing of class/array besides of scalar types.

I propose adding new type-hinting keyword 'scalar', which matches complement to currently possible hints. Think also about 'resource' hint.

Reproduce code:
---------------
<?php
        function show ( scalar $string ) {
                echo $string;
        }
        show("hello\n");
        show(new stdClass());
?>

Expected result:
----------------
hello
Error...