Remove dependence on Qt::this().
Remove dependence on QtCore4::isa.
Remove space-prefixed class names.
XS_AUTOLOAD no longer has to call perl methods.

But, it doesn't work. XS_AUTOLOAD can't tell if it was called via $object->method() or Qt::Object::method(), making it unusable. The current solution is to examine the op tree of the entersub op inside XS_AUTOLOAD, but that fails when running in the debugger, because the debugger calls it differently.