Fix: restructing session manager, ES6 -> ES5

src/game/menu/menu_typing_practice.js

@@ -69,7 +69,7 @@ var MenuTypingPractice = {
 		var screenBottomUI = new ScreenBottomUI();
 		// screenBottomUI.printLeftText("게임 진행 정보");
 		screenBottomUI.printCenterText("메뉴 > 타자 연습");
-		screenBottomUI.printRightText(sessionStorageManager.playerName);
+		screenBottomUI.printRightText(sessionStorageManager.getPlayerName());
 
 
 		this.makeActiveTypingPracticeAppButtons();
@@ -79,8 +79,8 @@ var MenuTypingPractice = {
 	makeActiveTypingPracticeAppButtons: function() {
 		var dbConnectManager = new DBConnectManager();
 		dbConnectManager.requestTypingPracticeAppList(
-			sessionStorageManager.maestroID,
-			sessionStorageManager.playerID,
+			sessionStorageManager.getMaestroID(),
+			sessionStorageManager.getPlayerID(),
 			(function(replyJSON) {
 				this.downloadListSucceeded(replyJSON);
 			}).bind(this),