fixes+changes:

- fixed windows build, using path, instead of path/filepath
- added switch + door, implemented relation (pair_system missing yet)
- fixed ldtk map loading, now using correct entitymap.png tileset

Makefile

@@ -19,6 +19,9 @@ build:
 buildwasm:
 	env GOOS=js GOARCH=wasm go build -o openquell.wasm $(LDFLAGS) .
 
+buildwindows:
+	GOOS=windows GOARCH=amd64 go build $(LDFLAGS) -o openquell.exe
+
 zipwasm:
 	zip -r openquell-$(SHORTVERSION).zip index.html openquell.wasm wasm_exec.js