ScriptConsole: Show current context

Show the current context in the script console. The expression
in the script console is evaluated within this context.

Change-Id: Ieb4cfc3e0892b150301f4ad79220cd878dee3ce3
Reviewed-by: hjk <qthjk@ovi.com>
Reviewed-by: Kai Koehne <kai.koehne@nokia.com>

src/plugins/debugger/stackhandler.h

@@ -87,6 +87,7 @@ public:
 
 signals:
     void stackChanged();
+    void currentIndexChanged();
 
 private:
     // QAbstractTableModel