FE/Qt: language string updates.
FE/Qt4-OSX: fix the translation of the application menu
FE/Qt4-NLS: merged pl
FE/Qt4-NLS: updated qt_* translation files to 4.4.3
FE/Qt4: updated Korean, Italian, Czech, Polish & Japanese translations
renamed VirtualBox4 to VirtualBox
purge the obsolete Qt3 GUI
FE/Qt: Updated Japanese and Polish translations.
FE/Qt: Updated French translation; added Arabic and Polish translations; fixed several English typos (in sources and in all translation files).