* Fix CPPLint errors in multiclass_nms, nccl, nce, reduce and save_load_combine

* Fix

* Add topk Python API.

* Add unit test.

* Remove the repeated API.

* Fix cpplint warnings in beam_search_decode_op

* Fix cpplint warnings in beam_search_op

* Fix test

* fix

* Fix conv_op.h

* Fix conv_mkldnn_op

* Fix cpplint issues in detection_map_op

- EPS added to softmax mkldnn primitive outcome is limited to training
phase

Fixes after review

clang format fixes

clang format fixes

* Fix CPPLint errors in operators

* Fix cast in softmax

* Fix softmax_mkldnn

* Fix send_recv_op_test

* Send_recv

* Fix softmax mkldnn

* Fix CPPLint errors in operators

* Fix prior box op

* Fix Prior Box op

* Fix top_k_op.cu

* Fix pool mkmldnn

* Fix pool mkmldnn

* init

* add some check

* add dist transpile logic

* add insert op for block

* init change get_pserver_program

* optimize code

* fix a bug

* can run now

* start to do table split

* start to process table gradient

* complete pserver part

* can send_vars now

* revert cpplint

* fix a bug

* optimize code

* move dist test to models

* revert the interface of distribute_transpiler.transpile

* fix prefetch_block

* optimize trainspiler code

* add comment to sum_op

* add warning log

* fix comment

* fix test_send_recv

* fix test_send_recv

* fix train with no distributed table

* optimize GetDims

* 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