Add an action to show/hide the mode bar on the far left.

Change-Id: If7a74eed7fc77b1d0fd5e4045671b3767fe2d7a2
Reviewed-by: Petar Perisin <petar.perisin@gmail.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>
(cherry picked from commit bde0627e59)

src/plugins/coreplugin/modemanager.h

@@ -66,9 +66,12 @@ public:
     static void addWidget(QWidget *widget);
 
     static void activateModeType(Id type);
-    static void setModeBarHidden(bool hidden);
     static void activateMode(Id id);
     static void setFocusToCurrentMode();
+    static bool isModeSelectorVisible();
+
+public slots:
+    void setModeSelectorVisible(bool visible);
 
 signals:
     void currentModeAboutToChange(Core::IMode *mode);