#6 Remove usage of K4AboutData in umbrello/main.cpp :

- In case QT_VERSION > 0x050000 remove #include <k4aboutdata.h> and
  remove #define KAboutData.
- Add implementation of function showGUI for case QT_VERSION > 0x050000.
- Change first argument of function initDocument to be insensitive to
  the Qt version (use QStringList in lieu of KCmdLineArgs).
- In function exportAllViews,
  - change arguments so that the function is agnostic to the Qt version
    used (pass in QString extension, QUrl directory, bool useFolders in
    lieu of KCmdLineArgs and exportOpt);
  - use qApp in lieu of kapp.
- In main program :
  - In case QT_VERSION > 0x050000,
    - add separate KAboutData related handling;
    - use QCommandLineParser;
    - provide handling of options "import-files", "import-directory",
      "export", "directory", "use-folders".
  - Change options "set-language-XYZ" (where XYZ are the supported
    programming languages) to single option "set-language" taking a
    separate argument for the programming language.