* Add C++ and python style check to travis.  
* Update all C++/python code that violate coding standards.

Fix some typos

* support manylinux build

* fix

* fix lib

* simplify image sample usage

* simplify image

* add scratch demo

* add scipy into dependency

* add demo

* update readme

* add better scratch demo

* add more data

* support mannul image

* init comment for sdk

* update comment

* init paddle

* add image writer

* change sample numble to 4

* add image and conv image

* add histogram

* rename test file

based on graphviz

* change paths

* add setup

* add packages

* update

* install ready

* restore mock

* restore graph_test.sh

* move visualdl.py to visualdl as a script

* fix setup

* remove onnx_pb2.py

* fix server_test

* add package into tests.sh

* add protobuf-compiler for package

* recover .git

* change script bin visualdl_bin to visualDL

* add npm cache

* avoid build_frontend in travis-CI

* avoid frontend build in travis-CI

* add pips

* restore protobuf mannul installation

* install protobuf

* fix package

* fix tool