adding appauthors to the args of createAboutDialog
adding appauthors to the args of createAboutDialog (required by YMGAAboutDialog)
- now provides two about boxes: Classic or Tabbed
- moved createPopupDialog inside Classic and Tabbed methods
- passing authors string as an argument to the constructor
- moving private methods to the private section
- start accept a type arguments to switch between Classic or Tabbed view
- constructor accepting the authors argument accordingly
invoking createAboutDialog also passing the authors argument