data: saving errors to Storage

* saving errors in separate sqlite table
* use MessageShowErrors to show the errors in the UI
* show error count permanently in the right side of the status bar with click to show
* fixed clicking of error locations
* fixed expanding of files with errors

src/lib/component/controller/GraphController.cpp

@@ -134,6 +134,11 @@ void GraphController::handleMessage(MessageGraphNodeMove* message)
 	}
 }
 
+void GraphController::handleMessage(MessageShowErrors* message)
+{
+	clear();
+}
+
 GraphView* GraphController::getView() const
 {
 	return Controller::getView<GraphView>();