autoload return value has no effect on other autoloaders
they will only be called based on whether the class has been loaded or
not.

As of PHP 5.3.2 PHP does not send class names with leading \ to
autoload functions.

Removed ltrim for '/' from autoload because it is

1. not needed: https://bugs.php.net/bug.php?id=50731 and
2. possibly wrong behavior: https://bugs.php.net/bug.php?id=51087

Added support for different response formats.
Support for error response in different formats.