Remove unused code and add short cut link

resources/strings/strings-zh-CN.properties

@@ -12,7 +12,7 @@ verifyImgDetail=验证图像
 saveDetail=保存标签文件
 openFileDetail=打开图像文件
 fitWidthDetail=调整宽度适应到窗口宽度
-tutorialDefault=YouTube教学(Default Web Browser, Recommended)
+tutorialDefault=YouTube教学
 tutorialChrome=YouTube教学(Chrome)
 info=版本信息
 shortcut=快捷键

resources/strings/strings-zh-TW.properties

@@ -12,7 +12,7 @@ verifyImgDetail=驗證圖像
 saveDetail=將標籤存到
 openFileDetail=打開圖像
 fitWidthDetail=調整到窗口寬度
-tutorialDefault=YouTube教學(Default Web Browser, Recommended)
+tutorialDefault=YouTube教學
 tutorialChrome=YouTube教學(Chrome)
 info=版本信息
 shortcut=快捷鍵

resources/strings/strings.properties

@@ -3,7 +3,7 @@ openFileDetail=Open image or label file
 quit=Quit
 quitApp=Quit application
 openDir=Open Dir
-copyPrevBounding=Copy previous Bounding Boxes in the current image 
+copyPrevBounding=Copy previous Bounding Boxes in the current image
 changeSavedAnnotationDir=Change default saved Annotation dir
 openAnnotation=Open Annotation
 openAnnotationDetail=Open an annotation file
@@ -33,7 +33,7 @@ delBox=Delete RectBox
 delBoxDetail=Remove the box
 dupBox=Duplicate RectBox
 dupBoxDetail=Create a duplicate of the selected box
-tutorialDefault=Tutorial(Default Web Browser, Recommended)
+tutorialDefault=Tutorial
 tutorialChrome=Tutorial(Chrome)
 tutorialDetail=Show demo
 info=Information