Version 3.7

After upgrading my Linux version to a newer release, where QT5 is now standard, some problems appeared. The default backend is now 'QtAgg', so that had to be added to screensize.py. It also turned out that zooming the application window caused problems when trying to drag that window. It would shrink down to a much smaller size. Since screensize.py finds the full screen size, there is no need to zoom (except on Windows platforms), so that has been removed for Linux and MacOS platforms. It is now possible to drag the window without shrinking it.