Documentation: Termbox crystal-lang wrapper.

[shayneoAtNorwood]

Theres a wrapper here that works rather well, from my experiments

https://github.com/andrewsuzuki/termbox-crystal

Could this be added to the README.cr ?

[nsf]

I'm lazy, send a pull request.

[shayneoAtNorwood]

I think I've done this right.......
#96

[nsf]

Merged.