* Add license to the top of files

* Add licenses agreement on the demo files

* 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

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

* Add test for graph edges

* add new line

* add google protobuf

* add onnx to travis

* install protoc and move installs to tests.sh

* tune protoc

* try to install onnx

* onnx always fails on travis, try script from onnx github

* install protobuf 3.1.0 but not onnx

* in the right dir

* tune path

* should work

* put onnx_pb2 there and it should work

* what if remove onnx_pb2.py

* cp compiled onnx_pb2 to the right place

* debug

* protoc

* install protoc

* chown

* test

* added protc, should work

* typo

* does it exist?

* hmmmm

* try dropbox

* test 1

* now it should work

* done

* make tests more thorough