smartcrop implementation in Go.

This is a fork of github.com/muesli/smartcrop with dependency on opencv removed, API simplifications and speed optimizatons.

smartcrop finds good crops for arbitrary images and crop sizes, based on Jonas Wagner's smartcrop.js

Image: https://www.flickr.com/photos/usfwspacific/8182486789 CC BY U.S. Fish & Wildlife

See https://godoc.org/github.com/artyom/smartcrop for API and usage example.