* Convolution fusion operator.
* Clean code
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* add cudnn ctc loss

* wip add test test=develop

* wip

* wip

* done test=develop

* move include cudnn test=develop

* test test=develop

* fix build test=develop

* fix build test=develop

* fix build on cudnn5 test=develop

* fix cudnn5 build test=develop

* fix cudnn5 build test=develop

* merge develop softmax functor change test=develop

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* 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

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Fix code to support cpplint syntax check

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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.

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Warning only at first when CUDA CC not matched.

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* Add affine grid generator.

* fix ffine grid.

* Add unitest.

* Add CPU kernel and fix unitest.

* Fix CPU kernel.

* Refine code.
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* Fix python api.
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* Update python api.
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* Fix comment.
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* Rename affine_grid_generator to affine_grid and enhence unitest.
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* Fix unitest.
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* feat(platform): lazy initialization of devicecontext in pool

Use std::async(deferer, []{...}) to lazy initialize DeviceContext in Pool

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* Add future includes

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