Other pure rust image processing and computer vision libraries

[imageproc](https://github.com/PistonDevelopers/imageproc)
[rust-vision](https://github.com/theotherphil/rust-vision)
[randomforest](https://github.com/theotherphil/randomforest)
[randomforest-demo](https://github.com/theotherphil/randomforest-demo)