- Replace CodeClimate with coveralls ?
- Get familar with jison
- git graph requires a blank line at the end. why?
- global.mermaid_config
- rewrite logger
- rewrite less code
- Setup code coverage
- Create a desktop client
- Fix sequence diagram node label position issue
- Fix flowchart interpolate/curve issue
    - not a common feature so dist/index.html cannot reproduce this issue
- Support customization of gantt diagram xAxis format
    - https://github.com/d3/d3-time-format#api-reference
    - https://bl.ocks.org/wboykinm/34627426d84f3242e0e6ecb2339e9065