Add action to jump to last tab.

Allows user to select a shortcut to jump to the far right tab.  There
is no default shortcut.

Patch by Francesco Cecconi <francesco.cecconi@gmail.com>
REVIEW: 102687
BUG: 279166
FIXED-IN: 4.8

src/ViewContainer.cpp

@@ -228,6 +228,11 @@ void ViewContainer::activateNextView()
     setActiveView( _views.at(index) );
 }
 
+void ViewContainer::activateLastView()
+{
+    setActiveView(_views.at(_views.count()-1));
+}
+
 void ViewContainer::activatePreviousView()
 {
     QWidget* active = activeView();