Feature/add clang format plugin

Fix badge's wrong link in Readme

* Merge conflict using theirs

* Because it is a cuda source file, and we need to support c++ 03 in
  cuda.

* Different Type compare.
* ostream << should pass a const object.
* remove always true checks.

*  because baidu/paddle transfered to paddlepaddle/paddle

Fix a pointer comparison bug in hl_dso_loader.cc

Fix several cpp issues

* Because it is a cuda source file, and we need to support c++ 03 in
  cuda.

Add new badges for docs and stats

*  because baidu/paddle transfered to paddlepaddle/paddle

Add style check for *.cc files in cuda directory

update srl demo

* Different Type compare.
* ostream << should pass a const object.
* remove always true checks.

Encourage users to file Github issues instead of emails.

modify directory structure in source code

Update sentiment_analysis.md

Sync Release Branch => Develop

Add Paddle Usage Stats Scripts.