Generated code in autoload_real.php should be namespaced

While collisions are effectively impossible due to the random (hashed?) class and function names, having the class and function in the global namespace is slightly annoying when doing work that involves `get_defined_functions` or `get_declared_classes` if any filtering of the resulting array is required, especially when using the namespace support in the Reflection APIs.

Unless there's a reason not to do this (which I'd be very interested in hearing), I'm more than happy to do the work and send a PR. I expect the file output would change from, roughly:

``` php