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

The description for vocabulary file is not consistent with the latest file

fix bug in inference.py

Fix PyHome Setted in PythonUtil.cpp

* set PYTHON_HOME outside the paddle processes.

fix docker image pythonhome

add seqtext_print for seqToseq demo

Fix dev image build error

paddle dist architecture (draft)

add field "prob" in paddle.infer

Add pre_scan routine to SequenceScanner.

support multi-field for inference

stride pooling for seqlastin and seqfirstin.