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

helpwindow.cpp

@@ -9,6 +9,7 @@ HelpWindow::HelpWindow(QWidget *parent) :
     ui(new Ui::HelpWindow)
 {
     ui->setupUi(this);
+    setWindowFlags(Qt::Window);
 
     m_helpEngine = new QHelpEngineCore(QApplication::applicationDirPath() +"/SavvyCAN.qhc", this);
     if (!m_helpEngine->setupData()) {