add example of clone(for_test)

added cycling the cifar and flowers datasets

* 1. Remove PYTHON_FLAGS from paddle_build.sh in paddlepaddle/paddle:latest-dev

* 1. Add PYTHON_FLAGS back
2. Change SIGKILL to SIGINT and SIGTERM

* 1. Add setup.py.in back

* 1. add pip install open-cv in Dockerfile to avoid libusb_exit hanging up which is caused by the opencv-python package missing

* 1. Add the && \ to line above

* 1. Remove the notice comment

fix mac compile

Fix log and relu layer

Add FAQ[libmkldnn.so.0 is not found when importing paddle.fluid]

fix mkldnn sum error

This reverts commit 4d8e8ee2, reversing
changes made to d6a9f005.

disable the LODTensor warning for now

Enhance Parallel Executor stable

Revert "MKLDNN layout: Support for sum operator"

* "add some api reference"

* "fix based on preview"

* "fix evaluator"

* "remove template doc"

* "add doc for exec"

* "add more changes"

* "fix based on preview"

* "chagne code format"

small thread-safety fix and doc improvements.

Add a ctest hung tool

move dist codes from  operaotrs/detail to operators/distributed

overlap rpc op memcpy in distributed training

Fix concat compile warning

Add bilinear interp supporting for uint8