Bug fix

Update downloader changed to DownloadManager
Fixed wierd download path
Fixed Crash on MainActivity
Fixed Crash when non-integer is inputted as Gallery ID

Version 4.13

app/src/main/res/values-ko/strings.xml

@@ -132,4 +132,6 @@
     <string name="proxy_dialog_server">서버</string>
     <string name="main_menu_thin">간단히 보기 모드</string>
     <string name="main_fab_cancel">다운로드 모두 취소</string>
+    <string name="channel_update">업데이트</string>
+    <string name="channel_update_description">업데이트 진행상황 표시</string>
 </resources>