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.

.gitignore

@@ -1,27 +1,11 @@
 # File created using '.gitignore Generator' for Visual Studio Code: https://bit.ly/vscode-gig
-# Created by https://www.toptal.com/developers/gitignore/api/windows,visualstudiocode,macos,linux,godot,executable,backup
-# Edit at https://www.toptal.com/developers/gitignore?templates=windows,visualstudiocode,macos,linux,godot,executable,backup
-
-### Backup ###
-*.bak
-*.gho
-*.ori
-*.orig
-*.tmp
-
-### Executable ###
-*.app
-*.bat
-*.cgi
-*.com
-*.exe
-*.gadget
-*.jar
-*.pif
-*.vb
-*.wsf
+# Created by https://www.toptal.com/developers/gitignore/api/godot,linux,macos,visualstudiocode,windows
+# Edit at https://www.toptal.com/developers/gitignore?templates=godot,linux,macos,visualstudiocode,windows
 
 ### Godot ###
+# Godot 4+ specific ignores
+.godot/
+
 # Godot-specific ignores
 .import/
 export.cfg
@@ -33,6 +17,7 @@ export_presets.cfg
 # Mono-specific ignores
 .mono/
 data_*/
+mono_crash.*.json
 
 ### Linux ###
 *~
@@ -56,8 +41,7 @@ data_*/
 .LSOverride
 
 # Icon must end with two \r
-Icon
-
+Icon
 
 # Thumbnails
 ._*
@@ -127,8 +111,7 @@ $RECYCLE.BIN/
 # Windows shortcuts
 *.lnk
 
-# End of https://www.toptal.com/developers/gitignore/api/windows,visualstudiocode,macos,linux,godot,executable,backup
+# End of https://www.toptal.com/developers/gitignore/api/godot,linux,macos,visualstudiocode,windows
 
 # Custom rules (everything added below won't be overriden by 'Generate .gitignore File' if you use 'Update' option)
 
-!export_presets.cfg