Relicense under MIT

I sort of pulled GPL out of a hat for this project thinking that no one would ever notice it. What I'm finding is that a permissive license will actually make it more useful for third parties and ultimately-slash-hopefully create even better tools for designers and prototypers which is the point, now, isn't it. :smile: 

To do this I need the permission of my two fantastic Frameless contributors

- [x] @koenbok 
- [x] @johnanthonyevans 

Please drop a comment below saying Yea. Thanks!