* Use aten version of is_signed.
* Define is_cuda native function and use it for variable.
* Use ATen dim for Variable dim/ndimension.
* Get rid of dim, ndimension fallthroughs in variable.py.
* Move size/stride Variable methods to use ATen.
* Implement shape property on Variable via ATen.
* Remove the _getattr__ function from Variable.
* Get rid of dispatch functions and avoid cast.
* Add THPUtils_packInt64Array.
* Throw python errors.
* Use fallthrough and fix fallthrough generation for native functions.
* is_cuda is a property, not a method.
