* 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

* link in eigen3 library to vl_test target
* Add new "template class SimpleWriteSyncGuard<Entry<long long>>;", since build will fail on OSX
* Add template keyboard to data<T>(0).Get() (otherwise this fails on OSX)
* Fix unit test in sdk_test.cc

Tested build and unit test run on OSX and Ubuntu with no issues

add_mode

avoid copy LogWriter