BUG: Fix interaction bug with laser pointer

Without this fix, although the first button press worked on any child widget of the set GUI widget, after this first click, no other button reacted to the interaction. Now all the buttons in the GUI widget work as expected.

Re KitwareMedical#43

GUIWidgets/qSlicerGUIWidgetsModuleWidget.cxx

@@ -338,7 +338,7 @@ void qSlicerGUIWidgetsModuleWidget::onStartInteractionButtonClicked()
     }
   else
     {
-    //std::cout << "No intersection was found... \n";
+    //std::cout << "No intersection was found \n";
     return;
     }
 
@@ -386,13 +386,11 @@ void qSlicerGUIWidgetsModuleWidget::onStartInteractionButtonClicked()
   QGraphicsSceneMouseEvent pressEvent(QEvent::GraphicsSceneMousePress);
   pressEvent.setScenePos(QPointF(xPositionPixels, yPositionPixels));
   pressEvent.setButton(Qt::LeftButton);
-  pressEvent.setButtons(Qt::LeftButton); 
   QApplication::sendEvent(texture->GetScene(), &pressEvent);
 
   // Send release event  
   QGraphicsSceneMouseEvent releaseEvent(QEvent::GraphicsSceneMouseRelease);
   releaseEvent.setScenePos(QPointF(xPositionPixels, yPositionPixels));
   releaseEvent.setButton(Qt::LeftButton);
-  releaseEvent.setButtons(Qt::LeftButton);
   QApplication::sendEvent(texture->GetScene(), &releaseEvent);
 }