Currently, Paddle only support Python use the sample version of
Protobuf that CPP do.

Refactor the ways to build docker image

Patch to release

Becasue of extern package.

For usage stats.

fix sphinx doc bug

Correct model average settings in crf

Fix Production Docker Image's mirror settings.

Timeout for caching in TravisCI

Fix travis ci error.

* `pip install` using `find` utility

Add pip install paddle wheel package in Dockerfile

fix build error with clang

Add more docs for paddle v2 api