* exhaustive search for cuDNN conv.
* Refine code and add unit testing.
* Fix model load in fluid/inference and unit testing in conv2d
* Follow comments.
* Fix compiling test=develop

test=develop

test=develop

test=develop

test=develop

test=develop

This reverts commit ce7d9b07.

* exhaustive search for cuDNN conv.
* Refine code and add unit testing.
* Clean code
* Fix model load in fluid/inference and unit testing in conv2d
* Follow comments.

test=develop

test=develop

1. Non utf-8 characters within comments of OPs may lead to protobuf fail to parse_from_string
2. comment out some ops which not supported on windows
3. cuda libs may not be correctly linked to target on windows

* add dam test

* update fuse_statis

* use separated dam model.

* Revert "use separated dam model."

This reverts commit 13e775c86f909b164b7cc1d35a8a24b964ec622e.

* test=develop

* modify the cmake file about infer test, test=develop.

* remove one comment, test=develop.

added depthwise conv mkldnn pass which for MKLDNN changes depthwise_conv operator to conv operator because for mkldnn this is the same api
test=develop

test=develop

test=develop

test=develop

test=develop

test=develop

test=develop

test=develop