2. refine trt 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

1. refine anakin engine
2. add data type for zero copy

align dev branch and PaddlePaddle:feature/anakin-engine brach
the cudnn workspace modify was not included for now, because we use a hard code way
in feature/anakin-engine branch. There should be a better way to implement it,
and subsequent submissions will be made.

test=develop

support change input size

* use anakin batch norm and scale implement fluid batch norm

cherry-pick feature/anakin-engine: add anakin softmax/transpose/batch_norm/flatten/reshape op (#16020)

* add anakin softmax/ flatten/reshape/transpose/batch_norm op converter

* add activation op

* test conv2d relu sigmoid tanh

* 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