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.cpp

@@ -337,9 +337,14 @@ void ModeManager::setFocusToCurrentMode()
     }
 }
 
-void ModeManager::setModeBarHidden(bool hidden)
+void ModeManager::setModeSelectorVisible(bool visible)
 {
-    d->m_modeStack->setSelectionWidgetHidden(hidden);
+    d->m_modeStack->setSelectionWidgetVisible(visible);
+}
+
+bool ModeManager::isModeSelectorVisible()
+{
+    return d->m_modeStack->isSelectionWidgetVisible();
 }
 
 ModeManager *ModeManager::instance()