(NOT READY)73270866 jekyll implementations for style guide

for migrate to jekyll, I updated existing files below:

- `package.json`
- `Gruntfile.coffee`
- `setup.sh`

Also add new directry `html/`. In `html/`, all html templates files are saved.

Generated html files are save into `demo/` directory.

Would be nice if we can move `header` in to it's own file and reuse it :smiley: