Introduced a QML-specific debugger tool bar

This one has the common debugger actions as well as the QML Observer
specific part. This makes sure those actions are generally available and
not only from the QML Observer dock widget.

The filter in the tool bar should still be moved back.

Reviewed-by: Christiaan Janssen <christiaan.janssen@nokia.com>

src/plugins/debugger/debuggerconstants.h

@@ -52,6 +52,7 @@ const char * const STEP                 = "Debugger.StepLine";
 const char * const STEPOUT              = "Debugger.StepOut";
 const char * const NEXT                 = "Debugger.NextLine";
 const char * const REVERSE              = "Debugger.ReverseDirection";
+const char * const OPERATE_BY_INSTRUCTION   = "Debugger.OperateByInstruction";
 
 const char * const M_DEBUG_VIEWS        = "Debugger.Menu.View.Debug";