config feature update

[jjung99]

I added json file feature.

[suhhee1011]

Hi jiyun, thank you for add the JSON file feature to my repository.
I just reviewed your pull request and I found that there is some error that needs some work on it.

1. It doesn't allow to accept the output option.
2. It doesn't ignore other options which are not available.
3. If the config file is missing any options, it does not have a default value specified.

I think it is good if these features are edited 👍

[jjung99]

Hi, I updated the cil.js file and added extra config test files.
Let me know if there is any confusion or issue!