add setWindowFlags(Qt::Window) to improve window management

* improves window handling a lot
	(on Linux GNOME 3 at least: quickly resizing windows left/right, not forced in foreground anymore etc.)
	setWindowFlags() inserted in all *window.cpp files except mainwindow
    * some whitespace at EOL trimmed

re/discretestatewindow.cpp

@@ -8,6 +8,7 @@ DiscreteStateWindow::DiscreteStateWindow(const QVector<CANFrame> *frames, QWidge
     ui(new Ui::DiscreteStateWindow)
 {
     ui->setupUi(this);
+    setWindowFlags(Qt::Window);
 
     modelFrames = frames;
     operatingState = DWStates::IDLE;