More useful panel selection overlay
https://files.facepunch.com/garry/c5dea16a-bb19-4317-b7ad-2c9168cda48e.png
Add GameScenePicker
Added panel picker
https://files.facepunch.com/garry/ed393fe0-c5db-499b-8bc8-a85747e2a0b7.mp4
IPanel.GetPanelAt uses RenderOrder