* Add license to the top of files

* Add licenses agreement on the demo files

* Complete audio data integration:
* Add num channels, sample width, sample rate as params
* Generate audio file with proper params

* clang format

* Audio integration to front end
* Add flask end point
* Read and decode audio data

* refract a typo

* fix clang format

* Make the frontend to fetch the data from the flask server.

* Provide loading animation.

* Fixed format style
Fix the issue where the display label not working.

* Provide a 2D 3D switcher.
Display the chart in 3D.

* Include PCA method to do dimension reduction

* Fix the style.

* Fix typo
Use === to compare type as well.

* Add manual Save feature.

* Fix the incorrect style

* Add feature to record Text

* Create a simple UI for text preview.

* Connect frontend with backend text data

* Move a constant from parameter to the body.
Remove test log

* Add Python 3 support

* Update protobuf to 3.5 and pybind to 2.2.2

* Update test scripts to use python -m

* Change zip/xrange/import usages

* Remove file generated by

* Graph viz set up (#282)

* Include the Graph requirement, GraphViz` in docs.

* Provide information to the ONNX format model export.

* Ask the user to download Graphviz via the website instead of brew.

* Make test and build scripts compatible with python 2 & 3

* A WITH_PYTHON3 option was added to cmake.

* setup.py will detect runing version python, and setup up WITH_PYTHON3 environemnt variable before calling build.sh

* build.sh and test.sh will handle WITH_PYTHON3

* Fix pybind warning

* Pass WITH_PYTHON3 correctly

* Fix coding style

* Add six for Python 2 and 3 Compatibility

* Fix coding style

VDL is set to retry an pybinded API call multiple times in case the call fails the first time.  The issue is the method lib.retry will sleep the thread for 2 seconds after an exception.  Since VDL was not running in threaded mode, this causes all request to the server to stop immediately, therefore even requests to get static resource are frozen.  This change enables threaded mode in flask. (#249)

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

* 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 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