refs #312 navigation bars, contributes also to #347

* allow to set/unset frameless mode in CDockWidget
* adjusted context menus
* adjusted style sheets
* ini settings for margins
* hidden info area to host floating widgets only visible when floating (allows to CDockInfoArea widgets)
* made some private slots non-virtual

src/blackmisc/blackmiscfreefunctions.h

@@ -177,6 +177,9 @@ namespace BlackMisc
     //! Bool to yes / no
     QString boolToYesNo(bool v, bool  i18n = false);
 
+    //! Bool to true / false
+    QString boolToTrueFalse(bool v, bool  i18n = false);
+
     //! Get local host name
     const QString &localHostName();