* Support int8 type.

* Add pad_constant_batch_size_like

* refine pad_op

* optimize memory

* fix auc layer and add check for auc op

* use input to check if states are inited

* optimize code

This reverts commit bf3c3496.

* "cherry picked operators changes"

* "remove duplicated code"

* "add constant setter"

* "add get expected kernel"

* "fix ci"

* "add fill constant"

* Add Preface

* Add demo code

* Save file

* Refine code

* seems can work

* use elementwise strategy

* Use ElementwiseComputeEx

* Add comments

* extract functions from operator

* Refine code

* Follow comment

* code refine

* follow comments

* follow comments

* refine conv cudnn enforce

* update

* update all cudnn ops

* fix