Stop timers on closing Atlas

Otherwise we might try to render a view when half the infrastructure is
already taken down, which results in segfaults or asserts.

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

source/tools/atlas/AtlasUI/ScenarioEditor/ScenarioEditor.cpp

@@ -699,6 +699,9 @@ void ScenarioEditor::OnClose(wxCloseEvent& event)
 		}
 	}
 
+	m_Timer.Stop();
+	m_RenderTimer.Stop();
+
 	m_ToolManager.SetCurrentTool(_T(""));
 
 	m_FileHistory.SaveToSubDir(*wxConfigBase::Get());