Improve some loops (use copy, style fix)

bot.go

@@ -621,7 +621,7 @@ func (b *Bot) SendAlbum(to Recipient, a Album, options ...interface{}) ([]Messag
 		return nil, errors.Errorf("api error: %s", resp.Description)
 	}
 
-	for attachName, _ := range files {
+	for attachName := range files {
 		i, _ := strconv.Atoi(attachName)
 
 		var newID string

options.go

@@ -107,17 +107,13 @@ func (og *ReplyMarkup) copy() *ReplyMarkup {
 	cp.ReplyKeyboard = make([][]ReplyButton, len(og.ReplyKeyboard))
 	for i, row := range og.ReplyKeyboard {
 		cp.ReplyKeyboard[i] = make([]ReplyButton, len(row))
-		for j, btn := range row {
-			cp.ReplyKeyboard[i][j] = btn
-		}
+		copy(cp.ReplyKeyboard[i], row)
 	}
 
 	cp.InlineKeyboard = make([][]InlineButton, len(og.InlineKeyboard))
 	for i, row := range og.InlineKeyboard {
 		cp.InlineKeyboard[i] = make([]InlineButton, len(row))
-		for j, btn := range row {
-			cp.InlineKeyboard[i][j] = btn
-		}
+		copy(cp.InlineKeyboard[i], row)
 	}
 
 	return &cp

util.go

@@ -192,8 +192,8 @@ func processButtons(keys [][]InlineButton) {
 		return
 	}
 
-	for i, _ := range keys {
-		for j, _ := range keys[i] {
+	for i := range keys {
+		for j := range keys[i] {
 			key := &keys[i][j]
 			if key.Unique != "" {
 				// Format: "\f<callback_name>|<data>"