use io.Reader when parsing urls

cmd/crawl/main.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"fmt"
+	"io"
+	"io/ioutil"
 	"net/http"
 	"os"
 
@@ -20,9 +22,14 @@ func main() {
 	for p := range spider.Pages(os.Args[1]) {
 		resp, err := http.Get(p.To)
 		if err != nil {
+			p.Err = err
 			failures = append(failures, p)
+			continue
 		}
+		io.Copy(ioutil.Discard, resp.Body)
+		resp.Body.Close()
 		if resp.StatusCode != http.StatusOK {
+			p.Err = fmt.Errorf("http status; got %s, want %s", http.StatusText(resp.StatusCode), http.StatusText(http.StatusOK))
 			failures = append(failures, p)
 		}
 	}