* Optimization of pool2d grad, first commit.

* remove useless print codes

* refine codes

* refine codes

* seal more operation into template specialization

* fix template struct error in MaxPool2dGrad.

* Fix header including error

* refine code with comment

* Seal the param-preparation codes into function for common use.

* Seal the param-preparation codes into function for common use.

* Seal the param-preparation into funciton and make it common for other kernels

* polish code and erase useless template speicalization

* Rerun triger

* rerun trigger