Open source license for code and data

[mlandauer]

I didn't spot an open source license. Could we have one pretty please! ;-)

[jeamland]

I've added an MIT license to the README. I'll work on propagating that through the actual source files later.

[mlandauer]

Awesome. Thank you! By the way I'm working on a little visualisation experiment using the group ticket data from here. Much appreciated for publishing it in a sane format! ;-)