Description:
------------
hello,

i'm building a test/debug framework for my apps
i think can be useful a function that provides the caller scope of a certain function/method

thank you

Reproduce code:
---------------
namespace;
echo get_caller_scope(); // returns "\" global scope

namespace Test\A;
echo get_caller_scope(); // returns Test\A

class CallerTest
{
     public static function gimme(){echo get_caller_scope();}
     public static function launch(){self::test();}
}

Test::gimme(); // returns Test\A
Test::launch(); // returns Test\A\CallerTest