Use new faster auto lowpp class implementation (#1244)

* Test the new AUTO_LOWPP_CLASS generation

* Updates for numeric array

* More cufile changes

* Fix externs

* Update with bugfix and dtype fix

* Free-threading fixes

* Fix free-threading

* Fix types

* More bugfixes

* Make pergpustats an array

* More fixes

* Fix test

* Add backward-incompatibility note

* Improve backward compatibility

* Restore comment

Author: mdboom