Major clean up and reorganization

- Upgraded to Godot 4
- Just remembered the basic principles are based on a tile editor, and dramatically simplified from there. Derp.
- New state machine and license display add-ons.
- Re-licensed under the GPL because Micropolis' assets aren't under a separate one.

addons/simple-state/icons/licenses/Visit Kenney.url

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+[InternetShortcut]
+URL=http://www.kenney.nl/

addons/simple-state/icons/licenses/Visit Patreon.url

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+[InternetShortcut]
+URL=https://www.patreon.com/kenney/

addons/simple-state/icons/licenses/board_game_icons.txt

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+	
+
+	Board Game Icons (1.0)
+
+	Created/distributed by Kenney (www.kenney.nl)
+	Creation date: 10-01-2022
+
+			------------------------------
+
+	License: (Creative Commons Zero, CC0)
+	http://creativecommons.org/publicdomain/zero/1.0/
+
+	This content is free to use in personal, educational and commercial projects.
+	Support us by crediting Kenney or www.kenney.nl (this is not mandatory)
+
+			------------------------------
+
+	Donate:   http://support.kenney.nl
+	Patreon:  http://patreon.com/kenney/
+
+	Follow on Twitter for updates:
+	http://twitter.com/KenneyNL

addons/simple-state/icons/licenses/game_icons+expansion.txt

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+
+###############################################################################
+
+	Game icon pack by Kenney Vleugels (www.kenney.nl)
+
+			------------------------------
+
+			        License (CC0)
+	       http://creativecommons.org/publicdomain/zero/1.0/
+
+	You may use these graphics in personal and commercial projects.
+	Credit (Kenney or www.kenney.nl) would be nice but is not mandatory.
+
+###############################################################################

addons/simple-state/icons/licenses/pictogrammers.txt

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+Pictogrammers Free License
+--------------------------
+
+This icon collection is released as free, open source, and GPL friendly by
+the [Pictogrammers](http://pictogrammers.com/). You may use it
+for commercial projects, open source projects, or anything really.
+
+# Icons: Apache 2.0 (https://www.apache.org/licenses/LICENSE-2.0)
+Some of the icons are redistributed under the Apache 2.0 license. All other
+icons are either redistributed under their respective licenses or are
+distributed under the Apache 2.0 license.
+
+# Fonts: Apache 2.0 (https://www.apache.org/licenses/LICENSE-2.0)
+All web and desktop fonts are distributed under the Apache 2.0 license. Web
+and desktop fonts contain some icons that are redistributed under the Apache
+2.0 license. All other icons are either redistributed under their respective
+licenses or are distributed under the Apache 2.0 license.
+
+# Code: MIT (https://opensource.org/licenses/MIT)
+The MIT license applies to all non-font and non-icon files.