* add gflags for C++ unittest

* fix compile on cudnn7

* update

* update

* make silent

* Fix MacOS compile

* Update GRPC

* Unset PROTOBUF_EXEC

* WIP send recv op

* WIP send recv

* put grpc impl in details

* put grpc impl in details

* update wip

* update proto

* update proto

* update proto

* clean cmake

* wip on op implementations

* wip on op implementations

* compile ok adding ut

* wip unitest

* add extern cares for linking

* wip add ut

* working version send recv

* revert optimizer.py

* update test cmake

* add libtool to dockerfile

* update cmake dependency

* update cmake depends

* update cmake grpc depends

* fix cmake dependency

* fix compile error

* fix compile

* follow comments

* update

* update copyfrom

* py_test support argument, test_image_classification_train support argument

* use REMOVE_ITEM to rm item from list in cmake

Use CUDA_ARCH_NAME=All in the paddle/scripts/docker/build.sh and remove 20 21(20) in cmake/cuda.cmake.

* Support the build for multiple architectures at one cmake command (iOS).

* Update the documentations.

1. Automatically detect GPU arch by default.
2. Specify -DCUDA_ARCH_NAME=All when releasing PaddlePaddle new version

and abandoned deprecated sum API interface

* init batch norm op

* prepare input output

* compute mean_out var_out save_mean save_var on CPU

* active is test

* use eigen to do computation

* complete batch norm forward

* set default momentum to 0.9

* add batch norm grad op in CPU

* add tensor_format and NHWC support, add python test

* add test training

* add batch norm gradient test

* improve comment, fix foward Python UnitTest

* add gradient test

* fix eigen warning

* follow name style

* fix a bug

* change float to T

* add simple forward test

* test with different place

* add backward test

* refine python test

* remove old python test code

* code clean

* follow code style

* update comment

* "add nccl enforce"

* Dev

* Update comment

* Add nccl test

* Follow comments

By shell command

```bash
sed -i 's#ifdef PADDLE_ONLY_CPU#ifndef PADDLE_WITH_GPU#g' `find ./paddle/ -name '*.h' -o -name '*.cc' -o -name '*.cpp' -o -name '*.c' -o -name '*.cu'`
sed -i 's#ifndef PADDLE_ONLY_CPU#ifdef PADDLE_WITH_GPU#g' `find ./paddle/ -name '*.h' -o -name '*.cc' -o -name '*.cpp' -o -name '*.c' -o -name '*.cu'`
```