* Fix the EditorUI not showing the correct palette baked into the level
and only showing the default. This was tricky because the palette UI
can only be configured at setup time but not updated later.
* Add a new default palette for the Blueprint theme. Blueprint has a
dark background, so the palette colors should be bright. This palette
is chosen when you start a map with the blueprint wallpaper.
* Add a background Canvas to the MenuScene. In the "New Level" screen,
the background canvas will update to show the wallpaper settings
you've chosen as a preview of the level theme you're about to create.
* To the MenuScene add the "Load Drawing" window UI.
* Displays the user's Levels and Doodads using rows of buttons, 4
buttons per row. Clicking the button loads the EditorScene with that
filename.
* Free Version does not display the Doodads label or button on this
menu screen.
* Debug mode: no longer enables the DebugOverlay (F3) by default, but
does now insert the current FPS counter into the window title bar.
* ui.Frame: set a default "mostly transparent" BG color so the frame
background doesn't render as white.
* Add the MenuScene which will house the game's main menus.
* The "New Level" menu is first to be added.
* UI lets you pick Page Type and Wallpaper using radio buttons.
* Page Type: Unbounded, Bounded (default), No Negative Space, Bordered
* Fix bugs in uix.Canvas to fully support all these page types.
