remove _showProgress because prepareRead() is now always called
Thanks to Burkhard for the hint.
The mainwindow msut not be instantiated before the translator gets loaded, otherwise it is not translated!
With this, starting with LANG=de ./kst2 gets kst2 in German :-)
I tried to adapt the path according to where .qm files are installed under Linux, I hope it works the same under Windows.
Connect the signal only when the _mainWindow instance exists
add missing tr() call to get the menu item translated
remove OpenGL support use ratser instead