* split api_spec document;test=document_fix

* change tools

* test=develop;test=document_fix

* test=develop;test=document_fix

* test=develop

* mv sampcd_processor.py to tools

test=develop test=document_fix

* update example script

test=develop test=document_fix

test=develop

* refine API.spec, test=develop

* add nn.py to test,test=develop

* fix by removing new.spec, test=develop, test=document_fix

* refine scripts when PYTHON_ABI is empty, follow partial comments, add extra cpp api doc, test=develop, test=document_fix

* remove extra doc changes, remove API.spec, test=develop

This PR fix the tag error in paddle_build.sh

* refine print_signatures.py to remove ComposeNotAligned, test=develop

* remove experimental_namespace, test=develop

* add train demo to paddle_build.sh

test=develop
test=document_preview

* code cleaning

* test=develop

test=develop

* remove program desc files

test=develop

* add test_train to CI

test=develop
test=document_preview

* make run.sh excutable

test=develop
test=document_preview

* switch with_mkl to off

test=develop
test=document_preview

* switch with_mkl to off

test=develop

* switch with_mkl to on

test=develop

* move test_fluid_lib_train to ci_py35

test=develop

* fix bugs of MKLDNN building

* rm build_train_lib(), test=develop

* restore tensor.h, test=develop

* change approve site ;test=develop

* test=develop

* modify paddle_build.sh for Paddle python3 version image generation, test=develop

* modify paddle_build.sh for Paddle python3 image generation, test=develop

* add exception exit on error example codes test=develop

test=develop

* change grad_op approval

* test=develop

* CI Add Reviewer Rules

* CI Add Reviewer Rules

* change git_files

* change git_files

* test=develop

* test=develop

* fix warpctc.dll not found issue, test=develop

* revert the linux platform change, test=develop

* delete warpctc_lib_path.h.in, test=develop

* add SetPySitePackagePath function

* fix warpctc.dylib not found issue on Mac, test=develop

* improve the paddle lib path setting logic, test=develop

* fix mac ci issue caused by test_warpctc_op unittest, test=develop

* tweak code, test=develop

* prun backward ops
test=develop

* test api example

* update python

* add sampcd_processor.py

* add if 0

* sort

* test paddle

* test paddle

* test paddle

* add whitelist

* change sampcd_processor.py

* change sampcd_processor.py

* change sampcd_processor.py

* add exit

* test=develop

* test=develop

test=develop

* remove the obsolete cmake options, test=develop

* remove unittests, test=develop

* delete options in paddle/scripts/paddle_build.sh

* change nproc 8

需要在avx_noavx build时候，生成dockerfile。
使用combine_avx_noavx 参数生成whl后发现不能build镜像，原因：没有生成dockerfile。需要添加生成dockerfile选项。

* add WITH_COVERAGE option, default OFF

test=develop

* add coverage for python sdk

test=develop

* fix code style

* fix COVERAGE_FILE path

test=develop

* remove coverage package

test=develop

* test = develop, run coverage as module

test=develop

test=develop

add luotao to approval requirements.txt