* move conv to pten

* move conv to pten; test=develop

* fix bug;

* add conv cudnn impl; test=develop

* update

* update operator; test=develop

* fix bug; test=develop

* move operator and prepared_operator to develop; test=develop

* resolve conflict; test=develop

* remove useless code;test=develop

* add depency ; test=develop

* fix bug;

* add sig.cc ; test=develop

* fix use_op error; test=develop

* fix bug; test=develop

* fix bug; test=develop

* add conv3d register; test=develop

* fix star gan and conv_nn_grad test failed; test=develop

* add header; test=develop

* manul to recover to develop;

* resolve confilct; test=develop

* remove useless code

* fix bug;

* remove conv2d_cudnn; test=develop

* fix bugs; test=develop

* fix cpu rocm compile bugs; test=develop

* fix blas error; test=develop

* fix compile bug; test=develop

* fix windows compile error; test=develop

* fix windows error; test=develop

* resolve confilct; test=develop

* use iwyu clean include, test=develop, test=win

* compilation error, test=develop

* fix compilation error2, test=develop

* fix compilation error3, test=develop

* fix compilation error4, test=develop

* fix compilation error5, test=develop

* fix compilation error6, test=develop

* fix compilation error7, test=develop

* fix compilation error8, test=develop

* fix compilation error8, test=develop

* fix compilation error10, test=develop

* fix compilation error11, test=develop

Error description optimize for the math dir

Error description optimize for math dir

1.support asymmetric padding;
    2.support padding algorithm:"SAME" and "VALID";
    3.support channel_last: data_format NHWC and NDHWC;
    4.change doc of python API and c++;

    test=develop, test=document_preview

* Fix more CPPLint issues

* Fix more CPPLint issues

* Fix more CPPLint issues

* Fix CPPLint issues in operators/math and operators/reader

There are mainly following fixes:

- take `DeviceContext` as the template parameter of math functors and OpKernel instead of `Place`
- remove `eigen_device` interface in base class  `DeviceContext`
- remove `GetEigenDevice` interface in `ExecutionContext` and base class `DeviceContext`
- remove unused `platform::EigenDeviceConverter`
- rename `REGISTER_OP_GPU_KERNEL` to `REGISTER_OP_CUDA_KERNEL`
- rename `USE_GPU_ONLY_OP` to `USE_CUDA_ONLY_OP`