* test=develop, fix space_to_depth_doc

* test=develop, refine indent

* test=develop, refine code

* test=develop, add api spec

Fix allocator bug

test=develop

* Disable compare for accuracy issue.

test=develop

* Add todo comments to show more information.

test=develop

Enhance gc to support deleting tensor buffer in advance

* test=develop, add install check

* test=develop, add install check scripts

* test=develop, refine language

* test=develop, add api spec

* test=develop, change cdn to bj to pass ci

test=develop

* extend the slice function for python
test=develop

* test=develop, add some Layers and tests

* test=develop, add more layers

* test=develop, add more layers

* test=develop, add force cpu option

* Update test_layers.py

remove pdb

* test=develop, refine code

Update INT8 calibration README

* fix cdn issue, test=develop

* fix memory optimize bugs, test=develop

* fix memory optimize bugs, test=develop

* remove add/sub_2 op, test=develop

* disable memory_optimize by default, test=develop

* disable inplace activation in python, test=develop

* fix unittests, test=develop

* fix unittests, test=develop

* bug-fix, test=develop

polish deepCF model to support real dataset

Cherry-pick from PaddlePaddle:feature/anakin-engine: Anakin subgraph support.

test=develop

Fix quantization hang bugs.

fix deadlink

* update jitkernel doc

test=develop

* follow comments

* follow comments

test=develop

test=develop

Checkpoint hotfix

* test fix fetch bar place for ce

* fix ps mode dist train in develop test=develop

* fix style check test=develop

* update test=develop

test=develop

test=develop

test=develop

Move cpu_quantize_* passes into mkldnn subfolder

test=develop

test=develop

test=develop

test=develop

* test=develop, fix ptb rnn

* test=develop, change cdn to bj to pass ci

* test=develop, fix ci

* add layer norm to Layers, add transformer prepare encoding

* little change

* finish encoder part

* add decoder part

* finish model part

* add test case and part of data feed

* add transformer test

* add to_parameter, add remove in set_attr

* test=develop, fix pos encoding bug, create_parameter with stantard name

* test=develop, rm dropout test in imperative

* test=develop, fix cpu error

* test=develop, fix minize bug

* test=develop, fix one hot not stop gradient

* test=develop, fix one hot not stop gradient

* test=develop, refine parameter name

* test=develop, fix transformer test in imperative mode

* test=develop, fix transformer test in imperative mode

* test=develop, fix boost and mkl download error

* test=develop, fix boost and mkl download error

* test=develop, fix ci and refine code

* test=develop, fix ci and refine code

test=develop

test=develop

fix ctest eager deletion disable bug
test=develop

test=develop

fix imperative varbase creation