* Inception fusion operator.
* Support horizontal layer fusion in conv_fusion_op.
* Search conv algo strategy for variable-length input.
   search N times and cache the searched algos. For other input, choose the algo of input whose area is closest to this input.

* wip

* wip

* refactor no.1 dir structure test=develop

* fix linking test=develop

* fix includes test=develop

* fix build test=develop

* fix build test=develop

* refine batch merge pass

* refine batch merge pass test=develop

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* Refine Dockerfile

* Add tasks, cmake gen

* Fix code error

* Disable compile after paddle_build.sh

* Refine

* Skip on PY35 CI

* Change env

* Refine paddle_build.sh

* Expose gen_fluid_lib

* Refine mkldnn.cmake

* Refine mkldnn.cmake

* Refine mkldnnlib

* Skip unstable tests

* refine parallel_exe
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* rename shared_var_device

* code refine

* add test_weight_decay

* remove Sort
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* Add SortForReduce
test=develop

* code refine
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* follow comment
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add module cleanup
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This reverts commit 7f6d8ace.

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* code style fix, test=develop

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* Make topk op support variable k.
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* Fix tensor type.
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