usb_interface_descriptor of an alternate interface without having to switch
to it.
* Add some reserve bytes to all classes and add some reserved virtual slots
where the objects are publically constructable.
* Remove the source compatibilty defines that were briding the old USB* with
the new BUSB* class names.
* Implement the usb_raw side of getting an alternate interface descriptor.
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24842 a95241bf-73f2-0310-859d-f6bbb57e9c96