Add convert output to JSON

[DarkoNedic]

I also added a description in the README.md file at the end.

Works in most cases. I guess it's not working for example when one has parsing errors as described in the README or other special cases.
Tested on formats given by some benchmark files created by Google, and the my-blob file.
Also tested on a file with user data received from a server for a game.

[mildsunrise]

Thanks for the PR 😊💙

I think I'll leave it open for now, because we'd need a proper CLI interface (with --help, option to read files, etc.) before adding a --json option.

Also, it's a bit hackish to parse the console output, it would be better to return the JSON object along with parsed. I'll work on that if I find some time :)

[scarept]

Any light/update on this? Any update will be more than appreciated
I honestly try to look into the code and do the same that DarkoNedic did but its the 2nd day im looking into Protobuf so I don't have the knowledge to understand everything just yet