Move to todotxt organization

[karbassi]

Hello @freitass

There's a new organization (@todotxt) managing the todo.txt format, todo.txt-cli, and other apps. It'd be great to move this repo there and get more group maintenance. Would you be willing to move this project over and join the team to manage your repo, with the help of others?

It's better to move it than fork it since the issues, wiki, and history will all move along with it.