func NewDownloader() *Downloader {
	return &Downloader{
		client: http.DefaultClient,
	}
}
NewDownloader creates a downloader with a default HTTP client
which is used to download files from the net.
package downloader
import (
	"archive/zip"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"path/filepath"
	"strings"
)
type Getter interface {
	Get(url, dir string) error
}
type Downloader struct {
	client *http.Client
}