Close unclosed files (#735)

* Cose unclosed files

* Close additional unclosed file

* Dont use defer in loop

* Removed missed instances of defer in loop

eBook/examples/chapter_11/static.go

@@ -16,6 +16,7 @@ func main() {
 	r = bufio.NewReader(r)
 	r = new(bytes.Buffer)
 	f, _ := os.Open("test.txt")
+	defer f.Close()
 	r = bufio.NewReader(f)
 	var s *bytes.Buffer = new(bytes.Buffer)
 	r = s

eBook/examples/chapter_12/cat.go

@@ -31,5 +31,6 @@ func main() {
 			continue
 		}
 		cat(bufio.NewReader(f))
+		f.Close()
 	}
 }

eBook/examples/chapter_12/gzipped.go

@@ -17,6 +17,7 @@ func main() {
 			err)
 		os.Exit(1)
 	}
+	defer fi.Close()
 	fz, err := gzip.NewReader(fi)
 	if err != nil {
 		r = bufio.NewReader(fi)

eBook/examples/chapter_12/read_files.go

@@ -24,5 +24,6 @@ func main() {
 		for line, _, err := r.ReadLine(); err != io.EOF; line, _, err = r.ReadLine() {
 			fmt.Printf("Lines: %v (error %v)\n", string(line), err)
 		}
+		fin.Close()
 	}
 }

eBook/exercises/chapter_12/cat_numbered.go

@@ -39,5 +39,6 @@ func main() {
 			continue
 		}
 		cat(bufio.NewReader(f))
+		f.Close()
 	}
 }