Login url fix when called from a module [skip ci]

fixes #33

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

Fixed autoloader behavior according to leading \

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

Fix in RequestPanel

Use `hasAttribute()` instead to avoid code duplication

Update radio and checkbox

ResizableAsset typo fix!

fixes initializing attributes in Sort class