* add double grad implementation for dygraph, test=develop

* polish code, add uts, test=develop

* fix place bug, test=develop

* polish codes, add more uts for coverages, test=develop

* add no_grad_set, test=develop

* add star gan ut, test=develop

* follow comments, test=develop

* refine grad maker, test=develop

* refactor tracer stage 1, test=develop

* merge develop to solve conflict third times, test=develop

* open dygraph op test, test=develop

* modify to_variable, test=develop

* modify input and output for dygraph, test=develop

* modify input and output for dygraph(fix bug), test=develop

* fix input processing of dygraph op test, test=develop

* fix bug, test=develop

* fix op test, test=develop

* fix forward bug for dygraph, test=develop

* fix mkldnn op test for forward, test=develop

* update nn.py for dygraph, test=develop

* fix crop_tensor_op, test=develop

* fix elementwise_mul_op, test=develop

* fix fill_op, test=develop

* fix some mkldnn op, test=develop

* open backward op test for dygraph, test=develop

* delete log, test=develop

* close backward op test for dygraph, test=develop

* fix bug for edit_distance_op and test_lstm_cudnn_op, test=develop

* fix optest backward bug for dygraph, test=develop

* fix optest backward bug for dygraph, test=develop

* close backward op test for dygraph, test=develop

* close backward op test for dygraph, test=develop

* open dygraph op test, test=develop

* fix op test for dygraph, fix GradOpDescMaker, test=develop

* fix bug for linear_chain_crf_op.h, test=develop

* remove log, test=develop

* remove log, test=develop

* remove log for op_test.py, test=develop

* remove log for op_test.py, test=develop

* fix bug for var_conv_2d_op, change PADDLE_ENFORCE, test=develop

* fix PADDLE_ENFORCE_EQ for hierarchical_sigmoid_op.cc, test=develop

* fix bug for test_increment_ngraph_op.py, test=develop

* fix lod for op test in dygraph, test=develop

* refactor op_test.py to reduce redundant code, test=develop

* fix lod optest, modify InputVar/OutputVar to HasInput/HasOutput, test=develop

* remove debug log, test=develop

* remove redundant code in base.py, test=develop

* fix some error in optest, test=develop

* fix ClearNoNeedBufferInputs function's bug for LoDTensor, test=develop

* refactor op_test.py, test=develop

* remove redundant writing, test=develop

* fix error(get tensor of the grad variable), test=develop

* fix test_concat_mkldnn test_conv2d_mkldnn, test=develop

* fix optest.py for get tensor of LoDTensor, test=develop

* fix optest.py for get tensor of LoDTensor, test=develop

* fix optest.py for get tensor of LoDTensor, test=develop

* fix some redundant code, test=develop

* reslove conflict and rewrite paddle error message, test=develop

Do not use ctor

* Reduce line of codes.
* We can use virtual function for Maker now.
* The implementation does not care what maker holds, it is easier to
refactor later.

* remove net op and cond_op

* fix cpplint

* fix dependency

* delete backward_test; fix compile

* disable batch_norm backward

* rm test_net.py

* make batchnorm test independent of backward.cc

* make test_layer_norm_op independent of backward.cc

* make test_layer_norm_op independent of backward.cc

* delete unused code

* clean up

* Fix cpplint errors, round2

* Fix pointer issue

* Rename XXDescBind --> XXDesc

* Fix Compile

* Move framework.proto to proto namespace

* Fix compile

* Fix compile

* Fix Compile

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`

* fix m_ops

* fix activation op

They are public now

* init Infershape

* add static InferShape interface

* refactor add-op infershape

* add AttrReader

* add all maker's infershape

* add all InferShape

* add python infer api

* add VarDesc interface

* add python VarDesc and OpDesc interface

* update python code

* use infershape function to do shape inference

* clean code

* do not use pointer

* refine code of op_proto_maker

* add get_dims to VarDesc

* refine the code

* remove the dependency from operator to op registry

* remove OpProtoAndCheckerMaker from operator

* restore complete_add_op

* add shape_infer_impl.h

* code optimization

* remove const return value

* add fake BlockDesc class

* optimize code

* remove infer function in op_info

* move InferShapeContextImpl to operator.h

* optimize the interface of InferShapeContextBase

* add temperary interface of new infershape

* change add_op, clip_op, conv2d_op and activation_op

* change all operators InferShape

* fix SetDim

* update cos_sim_op

* update crop_op

* update lookup_table_op

* allocate tensor when call GetDim in InferShapeContext

* update modified_huber_loss_op

* update rowwise_add_op

* update mean_op

* update sequence_avg_pool_op

* typo

* remove old InferShape interface

* can compile

* fix or unit test

* clean code

* clean code

* remove const before InferShapeContext

* change InferenceContextBase to pointer

* rename RunTime to Runtime, code clean

of identity to Y.