Fixed bug in not creating the Planning scene

1. Also some polishing to switching scenes.
Added layout constants

1. Currently just the map in MapView.
Added placeholder background to MapView

1. Just a blank, white screen.
Added click behavior and background to Planning

1. Goes to MapView on click.
2. Background is placeholder.
Fixed various bugs and behaviors in MainMenu

1. MainMenu wasn't freeing the background correctly.
2. Now goes to Planning on click.