* Complete re layout the documentation on PPO.

* Add how to develop in cn. Also rearrange the demo location.

* Update the doc to use CDN

* Update installation guide.

* Update the doc setting to use layout.html template

* Update the documentations to fix some grammer error

* Adjust the sync_cycle automatically.

* Change the multiplier type to double.

* Adjust the sync_period.

* Fix comment.

* Add the pre-commit

* Run pre-commit with other files.

* Update the version number
Update the doc to include Vue
Update the doc to give more details on the sync_cycle
Update the doc to include python 3

* Update the LogWriter constructor doc.

* Update the package copy directory.

* Update the version to 0.0.2 (implying beta now)

* Update the vdl_create_scratch_log to python 3 as well.

* add manylinux build

* update build.sh

* typo

* Display documentations of demos on the Docs.

* Rename the title from `demos` to `Examples`.

* Add the support to write documentation in the pybind directly.

* Provide more detail of the API documentations.

Update the link in how_to_dev_backend_en.md to the full path. This should resolve the issue where the API doc not building. (#288)

* 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.

* Adds backend / SDK dev doc

* Update per Varun and chanwei's comment

* Provide instructions on virtualenv.

* Clean up the detail a little bit.

* Add how to develop frontend documentation.

* Provide a bit of information on san file.

* fix some information error

* Update the documention.

* Simplify the documentation.

* Remove unnecessary sentences

* Add travis-ci job to deploy docs to visualdl.paddlepaddle.org.  Update readme's to correctly show all images.

* Add SSH known hosts

* Add in additional restrictions for documentation deploy:
* Only deploy on merge to 'develop' branch

Update the requirements.txt to include pre-commit

* Add the Chinese and English "Contribute Code" documentations.

* Provide some more detail messages in the documentations

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

Fix some typos

* add introduction

* update comment, add onnx, update some image

* add image-gan.png

* working on quick start

* quick start english

* init quick start

* add image

* add chinese introduction

* clean

* clean

* add graph

* fix path

* up

* add mdoel_pb

* modified something in frontend directory

* modified gitignore

* remove node_modules

* modify the data format for graph

* add label for each edge in the graph data formate

* merge scalars and image

* update histogram layout and style