* Enable INT8 Concat Kernel to improve the performance of MobileNet-SSD.
test=develop

* Optimize UT format.
test=develop

* Fix UT file address issue.
test=develop

* Refine the license year.
test=develop

* Optimize code for new API.
test=develop

* Restructure INT8 Concat kernel.
test=develop

* refine parallelExecutor
test=develop

* Polish op_handle
test=develop

* Remove unnecessary op_handle
test=develop

* Fix Travis CI
test=develop

* Fix fetch bug
test=develop

* Remove WaitInputVarGenerated

* Fix OpHandleBase::Run
test=develop

* debug
test=develop

* use origin fetch_op_handle
test=develop

* Revert op_handle_base.cc
test=develop

* Polish code
test=develop

* Fix OpHandleBase::Run
test=develop

* code refine

* test CI and CE
test=develop

* fix OpHandle::Run
test=develop

* refine AllReduceOpHandle
test=develop

* Polish code
test=develop

* refine fused_all_reduce_op

* add unit test in test_parallel_executor_seresnext
test=develop

* Rewrite gradient ProtoMaker for affine_channel_op to remove the Output as the input.
* Add act in Python API to make the act can be in-place by layer_help.py

* temoprarily disable the code of use kCUDNN, test=develop

* add TODO comment, test=develop

* Add enabling quantization

test=develop

* remove unused (here) function

* Enhance affine_channel_op infer-shape check

* save infer model bug fix, return target vars' name list

* Add softmax_with_cross_entropy_op test=develop

* simplify implementation test=develop

* fuse all_reduce
test=develop

* add fuse_parameter_groups_size
test=develop

* Polish code
test=develop

* Fix travis-ci
test=develop

* Add SetGroupAccordingToLayers and SetGroupAccordingToGroupSize
test=develop

* Add SetGroupAccordingToMemorySize
test=develop

* fix multi_devices_graph
test=develop

* reset params_grads
test=develop

* Polish code
test=develop

* take care edge cases test=develop

* use pragma test=develop

test=develop

* wip allreduce in op

* wip

* wip

* wip

* wip adding test

* wip for conflict with mp mode

* fix tests test=develop

* fix cpu build test=develop

* fix travis clang format test=develop

* fix cpu build test=develop

* update api.spec test=develop

* delete comment test=develop

* fix cpplint test=develop

* fix test=develop

* follow comment test=develop

* add file test=develop

* fix build test=develop

* update test=develop

* to be compatible with sync_bn, and fix mp mode in develop test=develop

test=develop

test=develop

* Make step_input support custom lod level.
test=develop

* Fix API.spec
test=develop

* Fix API.spec.
test=develop

* Fix API.spec
test=develop

* Add default value in document of step_input.
test=develop

* Fix document.
test=develop

* Fix API.spec
test=develop

test=develop