Prototypes for DefaultFrame, DownloadPanel and WelcomePanel committed

compile and execute DefaultFrame, it contains a JMenuBar and a contentPane
the contentPane initially show the welcomePane, if you click the Download Button the downloadPane will be shown

empty files are present: ExtractPanel, OverlayPanel, Play, ReplacePanel, StripPanel and TitleCreditPanel
Mergining remote repo (created online) with local repo.