This is possible now that we no longer support go1.12 and brings rclone into line with standard practices in the Go world. This also removes errors.New and errors.Errorf from lib/errors and prefers the stdlib errors package over lib/errors.
git grep -l github.com/ncw/rclone | xargs -d'\n' perl -i~ -lpe 's|github.com/ncw/rclone|github.com/rclone/rclone|g' goimports -w `find . -name \*.go`
